Administration Of Sumatriptan Research Articles

Additive Anticonvulsive Effects of Sumatriptan and Morphine on Pentylenetetrazole-Induced Clonic Seizures in Mice.

Sumatriptan protects the brain from damage and enhance the anti-seizure effect of morphine. There is evidence that nitric oxide (NO) may mediate these effects of both drugs. In the present study, we investigated the effects of sumatriptan (0.1-20 mg/kg, intraperitoneal [i.p.]) and morphine (0.1-20 mg/kg, i.p.) alone or in combination on seizure thresholds in an in vivo model of seizure in mice. Using various NO synthase inhibitors as well as the NO precursor, we assessed possible involvement of NO signaling in these effects. Clonic seizures were induced in male Naval Medical Research Institute mice by intravenous administration of pentylenetetrazol (PTZ). Acute sumatriptan administration exerted anti-convulsive effects at 0.5 (p<0.01) and 1 mg/kg (p<0.05), but pro-convulsive effects at 20 mg/kg (p<0.05). Morphine had anti-convulsive effects at 0.5 (p<0.05) and 1 mg/kg (p<0.001), but exerted pro-convulsive effect at 20 mg/kg (p<0.05). Combination treatment with sub-effective doses of sumatriptan (0.1 mg/kg) and morphine (0.1 mg/kg) significantly (p<0.05) exerted an anti-convulsive effect. Co-administration of the NO precursor L-arginine (60 mg/kg) with sub-effective doses of sumatriptan and morphine significantly (p<0.05) increased seizure threshold compared with sumatriptan alone, but not sumatriptan+morphine group. While concomitant administration of either the non-selective NO synthase (NOS) inhibitor L-NG-nitroarginine methyl ester (5 mg/kg) or the selective inducible NOS inhibitor aminoguanidine (50 mg/kg) with combined sub-effective doses of morphine and sumatriptan produced significant anticonvulsive effects, concomitant administration with the selective neuronal NOS inhibitor 7-nitroindazole (30 mg/kg) inhibited this effect. Our data suggest a possible role for the NO signaling in the anticonvulsive effects of combined sumatriptan and morphine on the PTZ-induced clonic seizures in mice.

Sumatriptan mitigates bleomycin-induced lung fibrosis in male rats: Involvement of inflammation, oxidative stress and α-SMA

IntroductionIdiopathic pulmonary fibrosis (IPF) is a fibrotic lung condition that produces symptoms including coughing which may cause by excessive accumulation of scar tissue inflammatory and oxidative stress exacerbation. Sumatriptan, utilized for migraine treatment as a selective 5-HT1B/1D receptor agonist, has demonstrated significant anti-inflammatory and antioxidant properties in multiple preclinical investigations. Operating primarily on serotonin receptors, sumatriptan leverages the diverse physiological functions of serotonin, playing a pivotal role in regulating both inflammation and oxidative stress which is particularly relevant in the context of IPF. Materials & methodsThirty-five male Wistar rats were divided to five group, including: Sham (without IPF induction), control (BLM 5 mg/kg, intraperitoneally), and three fibrosis group with sumatriptan (0.5, 1, and 3 mg/kg, i.p. for 2 weeks) administration. IPF was induced by injection of BLM (single dose, 5 mg/kg intratracheally). Lung tissues were separated for measurement of myeloperoxidase (MPO) as an oxidative stress hallmark, and tumor necrosis factor-α (TNF-α), interleukin-1β (IL-β), and transforming growth factor-β (TGF-β) as inflammatory markers as well as alpha smooth muscle actin (α-SMA). Also, for histological investigations, tissue damages were assessed by Hematoxylin-eosin (H&E) and Masson’s trichrome staining method. ResultsBLM-induced fibrosis could increase α-SMA, MPO, TNF-α, IL-1β, and TGF-β, while treatment with sumatriptan has reversed the α-SMA, MPO, and IL-1β levels. Moreover, the results of H&E and Masson’s trichrome staining indicated that sumatriptan (1 and 3 mg/kg) reduced tissue damages, alveolar wall thickness, collagen accumulation, and pulmonary fibrosis induced by BLM. ConclusionAccording to the data achieved from this study, Sumatriptan appears to have therapeutic benefits in IPF, possibly via reducing α-SMA as well as inflammation and the toxicity caused by oxidative stress.

Evaluation of the Impact of Ritlecitinib on Organic Cation Transporters Using Sumatriptan and Biomarkers as Probes.

Ritlecitinib, an inhibitor of Janus kinase 3 and hepatocellular carcinoma family kinases, is in development as potential treatment for several inflammatory diseases. In vitro studies presented ritlecitinib as an inhibitor of hepatic organic cation transporter (OCT) 1, renal transporters OCT2 and multidrug and toxin extrusion (MATE) proteins 1/2K using multiple substrates, and ritlecitinib's major inactive metabolite M2, as an inhibitor of OCT1. A clinical interaction study with an OCT1 drug probe (sumatriptan) and relevant probe biomarkers for OCT/MATE was conducted to assess the effect of ritlecitinib on these transporters in healthy adult participants. The selectivity of sumatriptan for OCT1 was confirmed through a series of in vitro uptake assays. A simple static model was used to help contextualize the observed changes in sumatriptan area under the plasma concentration-time curve (AUC). Coadministration of a single 400-mg dose of ritlecitinib increased sumatriptan AUC from time 0 to infinity (AUCinf ) by ≈30% relative to a single 25-mg sumatriptan administration alone. When administered 8 hours after a ritlecitinib dose, sumatriptan AUCinf increased by ≈50% relative to sumatriptan given alone. Consistent with OCT1 inhibition, the AUC from time 0 to 24 hours of isobutyryl-L-carnitine decreased by ≈15% after ritlecitinib. Based on the evaluation of the renal clearance of N1 -methylnicotinamide, ritlecitinib does not exert clinically meaningful inhibition on renal OCT2 or MATE1/2K. This study confirmed that ritlecitinib and M2 are inhibitors of OCT1 but not OCT2 or MATE1/2K in healthy adults.

Sumatriptan prevents central sensitization specifically in the trigeminal dermatome in humans

The exact mechanism and site of action of triptans in aborting migraine attacks remain under debate. We hypothesized that the clinical efficacy of triptans lies in aborting central sensitization and focused on the question of why triptans are headache specific, that is highly effective in migraine and cluster headache and ineffective in extracephalic pain. Forty healthy participants were enrolled in this double-blinded, randomized, placebo-controlled study. The effect of sumatriptan (n=20) versus placebo (n=20) was investigated in a trigeminal (V1) versus an extracephalic dermatome (forearm) using a topical capsaicin sensitization model. Capsaicin-induced primary and secondary hyperalgesia were evaluated using quantitative sensory testing. After capsaicin application, primary hyperalgesia developed in both the sumatriptan and placebo groups in both dermatomes. However, sumatriptan exclusively prevented secondary hyperalgesia in the V1 dermatome but not on the forearm. Placebo exerted no effects on secondary hyperalgesia in both trigeminal and extracephalic dermatomes. Additionally, sumatriptan reduced the flare size exclusively in the V1 dermatome. Our data suggest that sumatriptan reduces central sensitization (secondary hyperalgesia) without modulating peripheral sensitization (primary hyperalgesia) in a human pain model of capsaicin-induced sensitization. Moreover, despite a systemic administration of sumatriptan, the modulatory effects are trigeminal specific, echoing the clinical effect of triptans in aborting headaches, but not extracephalic pain. Our data suggest that triptans exert their efficacy by suppressing central sensitization. By revealing a dermatome-specific modulation, our study demonstrates a previously unrecognized interaction between the pharmacodynamics of triptans and the trigeminal nociceptive system that provides new insight into how triptans may work in aborting headache attacks.

Harnessing Intranasal Delivery Systems of Sumatriptan for the Treatment of Migraine.

Sumatriptan (ST) is a commonly prescribed drug for treating migraine. The efficiency of several routes of ST administration has been investigated. Recently, the intranasal route with different delivery systems has gained interest owing to its fast-acting and effectiveness. The present study is aimed at reviewing the available studies on novel delivery systems for intranasal ST administration. The oral route of ST administration is common but complicated with some problems. Gastroparesis in patients with migraine may reduce the absorption and effectiveness of ST upon oral use. Furthermore, the gastrointestinal (GI) system and hepatic metabolism can alter the pharmacokinetics and clinical effects of ST. The bioavailability of conventional nasal liquids is low due to the deposition of a large fraction of the delivered dose of a drug in the nasal cavity. Several delivery systems have been utilized in a wide range of preclinical and clinical studies to enhance the bioavailability of ST. The beneficial effects of the dry nasal powder of ST (AVP-825) have been proven in clinical studies. Moreover, other delivery systems based on microemulsions, microspheres, and nanoparticles have been introduced, and their higher bioavailability and efficacy were demonstrated in preclinical studies. Based on the extant findings, harnessing novel delivery systems can improve the bioavailability of ST and enhance its effectiveness against migraine attacks. However, further clinical studies are needed to approve the safety and efficacy of employing such systems in humans.

Onset of Transient Sadness Following the Concomitant Use of a Triptan and Selective Serotonin Reuptake Inhibitor/Serotonin Norepinephrine Reuptake Inhibitors Therapy: A Case Report

Background: Migraine and depression have a bi-directional, positive association. The likelihood of these conditions being comorbidities is high, thus, the possibility of concomitant use of an antidepressant and a triptan is also increased. Case Presentation: We present a case of a 39-year-old female with a history of migraine with aura and depression who had brief episodes of exacerbated depressive symptoms following oral administration of sumatriptan 100 mg daily as needed while taking various selective serotonin reuptake inhibitor (SSRI) and serotonin and norepinephrine reuptake inhibitor (SNRI) medications on different occasions. The patient experienced 30-minute episodes of sweating and subjective increase in temperature approximately 2–3 hours after administration of sumatriptan 100 mg. This was followed by a transient exacerbation of sadness described by the patient as unhappiness, hopelessness, and tearfulness, which lasted 1 to 2 hours. To date, there are no other published case reports that have described this particular presentation. Several studies have reported possible serotonin syndrome as a result of the combination. Current evidence and known pharmacological actions of SSRIs/SNRIs and triptans are not well-defined enough to explain how one can experience episodic worsening depression. Conclusion: This case illustrates that clinicians should consider other potential adverse effects of the combined use of triptans and SSRIs/SNRIs beyond serotonin syndrome.

Drug Treatment of Cluster Headache.

Cluster headache belongs to the group of trigeminal autonomic headaches. This review summarizes drug therapy of cluster attacks and prophylactic treatment. Neurostimulation methods are not addressed. The therapy for acute cluster attacks includes inhalation of 100% oxygen, subcutaneous administration of sumatriptan, and intranasal application of sumatriptan or zolmitriptan. Bridging therapy, which is used until oral prophylactic therapy is effective, is performed either with oral prednisolone or with a pharmacological block of the major occipital nerves. Best documented drugs for preventive treatment of cluster headache are verapamil and lithium, and possibly effective drugs are gabapentin, topiramate, divalproex sodium, and melatonin. The efficacy of monoclonal antibodies to the calcitonin gene-related peptide so far has been only demonstrated for episodic cluster headache. Several drug therapies are being investigated including ketamine, onabotulinumtoxinA, lysergic acid, and sodium oxybate.

A prolactin-dependent sexually dimorphic mechanism of migraine chronification.

Determination of possible sex differences in mechanisms promoting migraine progression and the contribution of prolactin and the prolactin long (PRLR-L) and short (PRLR-S) receptor isoforms. The majority of patients with chronic migraine and medication overuse headache are female. Prolactin is present at higher levels in women and increases migraine. Prolactin signaling at the PRLR-S selectively sensitizes nociceptors in female rodents, while expression of the PRLR-L is protective. Medication overuse headache was modeled by repeated sumatriptan administration in male and female mice. Periorbital and hindpaw cutaneous allodynia served as a surrogate of migraine-like pain. PRLR-L and PRLR-S isoforms were measured in the trigeminal ganglion with western blotting. Possible co-localization of PRLR with serotonin 5HT1B and 5HT1D receptors was determined with RNAscope. Cabergoline, a dopamine receptor agonist that inhibits circulating prolactin, was co-administered with sumatriptan. Nasal administration of CRISPR/Cas9 plasmid was used to edit expression of both PRLR isoforms. PRLR was co-localized with 5HT1B or 5HT1D receptors in the ophthalmic region of female trigeminal ganglion. A single injection of sumatriptan increased serum PRL levels in female mice. Repeated sumatriptan promoted cutaneous allodynia in both sexes but down-regulated trigeminal ganglion PRLR-L, without altering PRLR-S, only in females. Co-administration of sumatriptan with cabergoline prevented allodynia and down-regulation of PRLR-L only in females. CRISPR/Cas9 editing of both PRLR isoforms in the trigeminal ganglion prevented sumatriptan-induced periorbital allodynia in females. We identified a sexually dimorphic mechanism of migraine chronification that involves down-regulation of PRLR-L and increased signaling of circulating prolactin at PRLR-S. These studies reveal a previously unrecognized neuroendocrine mechanism linking the hypothalamus to nociceptor sensitization that increases the risk of migraine pain in females and suggest opportunities for novel sex-specific therapies including gene editing through nasal delivery of CRISPR/Cas9 constructs.

Chitosan coating of anionic liposomes containing sumatriptan succinate: a candidate for nasal administration

Objective(s): Sumatriptan is a routine medication in the treatment of migraine and cluster headache that is generally given by oral or parental routes. However, a substantial proportion of patients suffer severe side effects. Nasal administration is significantly effective in case of oral administration of drug gives an undesirable side effect. So, the purpose of the present study was to develop intranasal delivery systems of Sumatriptan succinate using nanoliposomes as container of a water-soluble drug and chitosan as a mucoadhesive polymer.Materials and Methods: Liposomal formulations containing Sumatriptan as well as chitosan-coated liposomal formulations with different phospholipids and different concentrations were prepared. The formulations were evaluated for their physicochemical properties, stability and Cytotoxicity on BEAS-2B cells.Results: The prepared liposomal formulations coated with chitosan containing Sumatriptan had a size range of 165±9.4to 258±6.4 nm, and the surface charge of the obtained formulations was measured between 32±6 and 40±5 mV. Also, the encapsulation efficiency of the formulations was also observed between 14.2±2.7% and 19±3.4%. Based on the obtained results of physicochemical studies, liposomes F2 was also tested for stability and toxicity and showed that the F2 liposomes retained its physicochemical properties for up to 3 months. Finally, the toxicity test of the mentioned formulation showed relatively low toxicity on BEAS-2B cells.Conclusion: In the presents study, stable liposomal formulations coated with chitosan containing Sumatriptan were prepared and studied. Based on the obtained, these formulations can be used in preclinical and animal studies for the nasal administration of Sumatriptan.

DAGLα Inhibition as a Non-invasive and Translational Model of Episodic Headache.

Recent findings suggested that Clinical Endocannabinoid Deficiency underlies the pathophysiology of pain disorders, including migraine and headache. In models of medication overuse headache induced by sustained administration of sumatriptan or morphine, 2-AG levels were selectively depleted in the periaqueductal gray (PAG) and anandamide (AEA) increased in the cortex suggesting distinct regulation of the endocannabinoid system during headache pain. These results led to the hypothesis that blockade of DAGL, to reduce 2-AG levels would induce headache-like behaviors as a new, translationally relevant model of episodic headache. Our study investigated whether non-selective and selective blockade of DAGL, the main biosynthetic enzyme for 2-AG, induced periorbital and hind-paw allodynia, photophobia, anxiety-like behaviors, responsivity to abortive anti-migraine agents, and 2-AG/AEA levels. Injection of non-selective DAGL (DH376, 10 mg/kg, IP) and selective DAGLα (LEI106, 20 mg/kg, IP) inhibitors, but not DAGLβ agents, induced facial sensitivity in 100% and ∼60% of female and male rats, respectively, without induction of peripheral sensitivity. Notably, male rats showed significantly less sensitivity than female rats after DAGLα inhibition, suggesting sexual dimorphism in this mechanism. Importantly, LEI106 induced periorbital allodynia was attenuated by administration of the clinically available abortive antimigraine agents, sumatriptan and olcegepant. Selective DAGLα inhibition induced significant photophobia as measured by the light-dark box, without anxiety like behaviors or changes in voluntary movement. Analysis of AEA and 2-AG levels at the time of peak pain sensitivity revealed reductions in 2-AG in the visual cortex and periaqueductal gray (PAG), without altering anandamide or significantly increasing diacylglycerol levels. These results provide foundational evidence for DAGL-2AG in the induction of headache-like pain and photophobia without extracephalic allodynia, thus modeling the clinical episodic migraine. Mechanistically, behavioral measures of headache sensitivity after DAGL inhibition suggests that reduced 2-AG signaling in the cortex and PAG, but not the trigeminal nucleus caudalis or trigeminal ganglia, drives headache initiation. Therefore, episodic DAGL inhibition, which reduces the time, cost, and invasiveness of currently accepted models of headache, may fill the need for episodic migraine/headache models mirroring clinical presentation. Moreover, use of this approach may provide an avenue to study the transition from episodic to chronic headache.

A phase 1 randomized study of hemodynamic effects and pharmacokinetic interactions during concomitant use of rimegepant and sumatriptan in healthy adults

Objective: This randomized, partially-blinded, placebo-controlled study evaluated hemodynamic effects, pharmacokinetic interactions, and safety of concomitant administration of oral rimegepant and subcutaneous sumatriptan. Methods: Healthy non-smokers aged ≥18 and ≤40 years (men) or ≥18 and ≤50 years (women) were enrolled. On Day 1, subjects received 12 mg of sumatriptan as 2 subcutaneous 6 mg injections separated by 1 hour. From Days 2 to 4, subjects received rimegepant or placebo once daily (randomized 6 to 1, rimegepant to placebo). On Day 5, subjects received rimegepant or placebo, followed 2 hours later by 2 subcutaneous 6 mg injections of sumatriptan, separated by 1 hour. Sumatriptan was administered at the same times as on Day 1. Results: All 42 dosed subjects were analyzed. There were no significant differences in the time-weighted average of mean arterial pressure, diastolic blood pressure, or systolic blood pressure between treatment with rimegepant + sumatriptan and sumatriptan alone. Co-administration of rimegepant and sumatriptan had no effect on the pharmacokinetics of either drug. Overall, 93% (39/42) of subjects experienced ≥1 adverse event; injection site reaction was most common (60% [29/42]). Conclusions: Concomitant administration of oral rimegepant and subcutaneous sumatriptan to healthy adults was without hemodynamic or pharmacokinetic interaction and was safe and well tolerated.

Enhanced post-traumatic headache-like behaviors and diminished contribution of peripheral CGRP in female rats following a mild closed head injury.

Females are thought to have increased risk of developing post-traumatic headache following a traumatic head injury or concussion. However, the processes underlying this susceptibility remain unclear. We previously demonstrated the development of post-traumatic headache-like pain behaviors in a male rat model of mild closed head injury, along with the ability of sumatriptan and an anti-calcitonin-gene-related peptide monoclonal antibody to ameliorate these behaviors. Here, we conducted a follow-up study to explore the development of post-traumatic headache-like behaviors and the effectiveness of these headache therapies in females subjected to the same head trauma protocol. Adult female Sprague Dawley rats were subjected to a mild closed head injury using a weight-drop device (n = 126), or to a sham procedure (n = 28). Characterization of headache and pain related behaviors included assessment of changes in cutaneous cephalic and extracephalic tactile pain sensitivity, using von Frey monofilaments. Sensitivity to headache/migraine triggers was tested by examining the effect of intraperitoneal administration of a low dose of glyceryl trinitrate (100 µg/kg). Treatments included acute systemic administration of sumatriptan (1 mg/kg) and repeated systemic administration of a mouse anti-calcitonin gene-related peptide monoclonal antibody (30 mg/kg). Serum levels of calcitonin gene-related peptide were measured at baseline and at various time points post head injury in new cohorts of females (n = 38) and males (n = 36). Female rats subjected to a mild closed head injury developed cutaneous mechanical hyperalgesia, which was limited to the cephalic region and was resolved 4 weeks later. Cephalic pain hypersensitivity was ameliorated by treatment with sumatriptan but was resistant to an early and prolonged treatment with the anti-calcitonin gene-related peptide monoclonal antibody. Following the resolution of the head injury-evoked cephalic hypersensitivity, administration of glyceryl trinitrate produced a renewed and pronounced cephalic and extracephalic pain hypersensitivity that was inhibited by sumatriptan, but only partially by the anti-calcitonin gene-related peptide treatment. Calcitonin gene-related peptide serum levels were elevated in females but not in males at 7 days post head injury. Development of post-traumatic headache-like pain behaviors following a mild closed head injury, and responsiveness to treatment in rats is sexually dimorphic. When compared to the data obtained from male rats in the previous study, female rats display a prolonged state of cephalic hyperalgesia, increased responsiveness to a headache trigger, and a poorer effectiveness of an early and prolonged anti-calcitonin gene-related peptide treatment. The increased risk of females to develop post-traumatic headache may be linked to enhanced responsiveness of peripheral and/or central pain pathways and a mechanism independent of peripheral calcitonin gene-related peptide signaling.

Low-dose interleukin-2 reverses behavioral sensitization in multiple mouse models of headache disorders.

Headache disorders are highly prevalent and debilitating, with limited treatment options. Previous studies indicate that many proinflammatory immune cells contribute to headache pathophysiology. Given the well-recognized role of regulatory T (Treg) cells in maintaining immune homeostasis, we hypothesized that enhancing Treg function may be effective to treat multiple headache disorders. In a mouse model of chronic migraine, we observed that repeated nitroglycerin (NTG, a reliable trigger of migraine in patients) administration doubled the number of CD3 T cells in the trigeminal ganglia without altering the number of Treg cells, suggesting a deficiency in Treg-mediated immune homeostasis. We treated mice with low-dose interleukin-2 (ld-IL2) to preferentially expand and activate endogenous Treg cells. This not only prevented the development of NTG-induced persistent sensitization but also completely reversed the established facial skin hypersensitivity resulting from repeated NTG administration. The effect of ld-IL2 was independent of mouse sex and/or strain. Importantly, ld-IL2 treatment did not alter basal nociceptive responses, and repeated usage did not induce tolerance. The therapeutic effect of ld-IL2 was abolished by Treg depletion and was recapitulated by Treg adoptive transfer. Furthermore, treating mice with ld-IL2 1 to 7 days after mild traumatic brain injury effectively prevented as well as reversed the development of behaviors related to acute and chronic post-traumatic headache. In a model of medication overuse headache, Ld-IL2 completely reversed the cutaneous hypersensitivity induced by repeated administration of sumatriptan. Collectively, this study identifies ld-IL2 as a promising prophylactic for multiple headache disorders with a mechanism distinct from the existing treatment options.

Subcutaneous sumatriptan: association with decreases in postoperative pain and opioid use after elective cranial surgery.

Sumatriptan, a serotonin receptor agonist, has been used in the management of primary headache disorders and has been shown to affect trigeminal dural afferents. There is limited literature on the safety and efficacy of sumatriptan for postcraniotomy pain management. This study aimed to identify whether subcutaneous sumatriptan is a safe and efficacious pain management strategy after elective craniotomy. The authors retrospectively reviewed patients who underwent supratentorial or suboccipital craniotomy between 2016 and 2019 that was performed by a single provider at a single institution to identify patients given subcutaneous sumatriptan in the postoperative period. Pain scores and intravenous and oral opioid use were compared in patients with (n = 15) and without (n = 45) sumatriptan administration. Patients with and without sumatriptan administration had no significant differences in baseline characteristics or surgery type. There were no sumatriptan-related complications. The average pain score decreased from 3.9 to 1.3 within 1 hour after sumatriptan administration (p = 0.014). In both adult and pediatric patients there was decreased postoperative pain (adults: pain score of 1.1 vs 7.1, p < 0.001; pediatric: 1.1 vs 3.9, p = 0.007) within the first 48 hours. There were decreases in intravenous opioid use, length of intravenous opioid use, maximum dose of intravenous opioid used, oral opioid use, length of oral opioid use, and maximum dose of oral opioid used in both adult and pediatric patients. The authors identified subcutaneous sumatriptan as a safe and efficacious tool for postoperative pain management after craniotomy. Large multicenter randomized controlled studies are needed to further evaluate the specific role of sumatriptan in postoperative pain management after craniotomy.

Involvement of nNOS, and α1, α2, β1, and β2 Subunits of Soluble Guanylyl Cyclase Genes Expression in Anticonvulsant Effect of Sumatriptan on Pentylenetetrazole-Induced Seizure in Mice.

Epileptic seizure is phenomenon of abnormal synchronous neuronal discharge of a set of neurons in brain as a result of neuronal excitation. Evidence shows the nitric oxide (NO) involvement in neuronal excitability. Moreover, the role of cyclic guanosine monophosphate (cGMP) activation in seizure pathogenesis is well-established. Sumatriptan is a selective agonist of 5-Hydroxytryptamine1B/D auto-receptor, has been reassessed for its neuroprotection. This study was aimed to explore the anticonvulsant effect of sumatriptan through possible involvement of NO-cGMP pathway in mice. For this purpose, the protective effect of sumatriptan on PTZ-induced clonic seizure threshold (CST) was measured using NO-cGMP pathway inhibitors including N(G)-nitro-L-arginine (L-NNA, 1, 5, and 10 mg/kg), 7-nitroindazole (7-NI, 30, 45, and 60 mg/kg), aminoguanidine (AG, 30, 50, and 100 mg/kg), methylene blue (MB, 0.1, 0.5, and 1 mg/kg) and sildenafil (5, 10, and 20 mg/kg). The involvement of nitrergic system was further confirmed by measurement of nitrite levels by Griess reaction. The gene expression of neuronal nitric oxide synthase (nNOS) and subunits of soluble guanylyl cyclase (sGC) was studied using qRT-PCR analysis. Acute administration of sumatriptan (1.2 and 0.3 mg/kg) in combination with subeffective doses of NOS, sGC, and phosphodiesterase 5 inhibitors significantly reversed the PTZ-induced CST (P ≤ 0.001). The nitrite level in prefrontal cortex was significantly attenuated by sumatriptan (P ≤ 0.01). Furthermore, sumatriptan downregulated the PTZ-induced mRNA expression of nNOS (P ≤ 0.01), α1 (P ≤ 0.001), α2 (P ≤ 0.05), and β1 (P ≤ 0.05) genes in cerebral cortex of mice. In conclusion, the anticonvulsant activity of sumatriptan at least, in part, is mediated through inhibiting NO-cGMP pathway.

Inhibition of ovalbumin-induced allergic rhinitis by sumatriptan through the nitric oxide pathway in mice

AimsAllergic rhinitis is a global cause of disability, characterized by airway inflammation. Sumatriptan is a 5-hydroxytryptamine 1B/1D (5HT1B/1D) agonist used as a treatment for migraine headaches. Activation of 5HT1B/1D receptors can inhibit the release of neuropeptides and inhibit the inflammation cascades. This study investigated the effect of sumatriptan on ovalbumin-induced allergic rhinitis model in mice and the role of nitric oxide. MethodsFemale Balb/c mice were sensitized by intraperitoneal ovalbumin and challenged by intranasal ovalbumin. Mice received sumatriptan in doses 3, 10, 30 μg/kg intraperitoneally, 30 min before the last ovalbumin challenge. Key findingsIntraperitoneal injection of sumatriptan significantly decreased the nasal scratching, IL-4 and serum IgE levels of allergic mice, but it increased IFNγ levels. Histopathological analysis showed that the number of eosinophils was significantly elevated in nasal mucosa of ovalbumin-induced allergic mice, while sumatriptan treatment significantly reduced the number of eosinophils. GR-127935, a selective 5-HT1B/1D-receptor antagonist, reversed the anti-allergic effects of sumatriptan. Acute administration of l-NAME, a non-specific inhibitor of nitric oxide synthase, along with sumatriptan attenuated the anti-allergic effects of sumatriptan but chronic administration of l-NAME did not affect the influences of sumatriptan. Furthermore, sumatriptan decreased the inducible nitric oxide synthase (iNOS) protein expression in allergic mice, but it did not change the concentration of eNOS protein. SignificanceThis study shows that sumatriptan administration is associated with anti-allergic effects which are through 5HT1B/1D receptors. Decrease in iNOS expression and changes in T-helper 1&2 cytokines levels may indicate the involvement of inducible NOS and inflammation.

The effects of acute sumatriptan treatment on renal ischemia/reperfusion injury in rat and the possible involvement of nitric oxide.

Renal ischemia/reperfusion (I/R) injury is a common pathological condition. Studies reported renal toxicity following administration of triptans, which are commonly used for treating migraine headaches. To investigate the effects of sumatriptan and the molecular mechanisms involved in renal I/R injury in rats, ischemia was induced by bilateral clamping of renal pedicles followed by 24 h of reperfusion. Sumatriptan was administered in three different doses (5, 10, and 20 mg/kg) before I/R injury induction. Biochemical and histopathological changes were evaluated. The contribution of nitric oxide in modulating the effects of sumatriptan was determined by administrating aminoguanidine at 50 mg/kg 60 min before I/R injury. The tissue level of nitrite, superoxide dismutase (SOD), and malondialdehyde (MDA) were measured. Sumatriptan at 10 and 20 mg/kg increased the serum level of creatinine (Cr) and blood urea nitrogen (BUN) significantly. There was also a significant increase in nitrite level of animals that received 10 mg/kg sumatriptan. Co-administration of sumatriptan with aminoguanidine significantly decreased the BUN and Cr. Depletion of SOD level (P < 0.05) and elevation of serum levels of MDA (P < 0.001) indicated the involvement of oxidative stress in sumatriptan adverse effects. Overall, the administration of sumatriptan intensified renal I/R injury through activation of inducible nitric oxide synthase and oxidative responses in rats.

Protective effects of sumatriptan on ischaemia/reperfusion injury following torsion/detorsion in ipsilateral and contralateral testes of rat.

This study was planned to evaluate the effects of sumatriptan, 5-HT1B/1D receptors agonist, on ischaemia/reperfusion injury in bilateral testes after unilateral testicular torsion/detorsion in rats. Male Wistar rats (n=42) were allocated into a sham-operated group, a control group and treatment groups which were injected sumatriptan (0.1, 0.3 and 1mg/kg), GR-127935(0.01 mg/kg)-5-HT1B/1D receptors antagonist-and sumatriptan(0.1 mg/kg)+GR-127935(0.01 mg/kg). Torsion was induced for 1hr by rotating right testis 7200 in the clockwise direction, and after 7days of detorsion, bilateral orchiectomy was conducted. While the level of TNF-α rose in testicular tissue after inducing torsion/detorsion, sumatriptan injection notably lowered TNF-α level in ipsilateral (torted) and contralateral (nontorted) testes (p<0.001). Moreover, after inducing testicular torsion/detorsion, SOD activity was decreased, whereas administration of sumatriptan significantly increased SOD activity in bilateral testes (p<0.001). After induction of torsion/detorsion, macroscopic and histological analyses also showed severe damages which were improved by sumatriptan injection. Interestingly, co-administration of sumatriptan with GR-127935 reversed the beneficial impacts of sumatriptan on macroscopic appearance, microscopic pattern and biochemical markers. It is concluded that sumatriptan presumably via stimulation of 5-HT1B/1D receptors decreased inflammation, oxidative stress and deteriorations induced by ischaemia/reperfusion injury following testicular torsion/detorsion.

Prolonged Sumatriptan Treatment Differentially Alters 5HT1 Receptor‐mediated Signaling In Rat Trigeminal Ganglion

Medication Overuse Headache (MOH) is caused by repeated use of analgesics, such as triptans, which are used to treat migraines. Triptans are agonists at serotonin (5‐HT) type 1 receptors (5‐HT1B, 5‐HT1D, and 5‐HT1F), which are G protein‐coupled receptors known to couple to both Gi protein‐dependent (e.g., inhibition of cAMP production) and Gi protein‐independent (e.g., extracellular signal regulated kinase, ERK) signaling. Activation of 5HT1 receptors by triptans produce relief of migraine pain largely by inhibiting peripheral pain sensing neurons (nociceptors) of the trigeminal ganglia. However, the mechanism by which repeated/prolonged use of triptans causes MOH is unknown. We hypothesize that repeated or prolonged triptan exposure alters 5‐HT1 receptor‐mediated signaling from inhibitory to excitatory as a result of differential desensitization and/or signal switching in nociceptors. In this study, we examined the effects of prolonged treatment with the prototypical triptan, sumatriptan, on 5‐HT1 receptor‐mediated inhibition of PGE2‐stimulated cAMP accumulation and activation of ERK in rat trigeminal ganglia (TG) primary cultures.Incubation of TG cultures with the 5‐HT1 receptor agonists, 5‐carboxamidotryptamine (5‐CT) or sumatriptan (SUMA) produced a dose dependent inhibition of PGE2‐stimulated cAMP accumulation with an EC50 of 7.7 nM and 6.8 nM and a maximal inhibition of 59% and 45% for 5‐CT and SUMA, respectively. Pretreatment of TG cultures for 24h with SUMA (1 μM) followed by a rigorous washout step had no effect on the ability of 5‐CT to inhibit PGE2‐stimulation of cAMP accumulation. By contrast, rather than an inhibition of cAMP accumulation, SUMA increased PGE2‐mediated cAMP accumulation in TG cultures pretreated for 24h with SUMA suggesting that a switch from 5‐HT1 receptor‐mediated activation of Gi‐ to Gs‐proteins may have occurred. Although both 5‐CT and SUMA increased ERK activity by 40% above basal within 5 min of incubation, by contrast to effects on cAMP signaling, ERK activation in response to 5‐CT was lost whereas responses to SUMA were unaltered in TG cultures pretreated 24h with SUMA. Interestingly, similar to effects on SUMA‐mediated signaling, following 24h pretreatment with SUMA, 5‐HT‐mediated ERK activation was unaltered whereas 5‐HT‐mediated inhibition of cAMP accumulation was no longer observedThese results support our hypothesis that prolonged exposure to a triptan may produce MOH by inducing differential desensitization of 5‐HT1 receptor signaling pathways and signal switching in nociceptors. Future experiments will determine if repeated in vivo administration of sumatriptan will similarly alter 5‐HT1 receptor signaling in rat trigeminal ganglia nociceptors.Support or Funding InformationSupported by NIH/NINDS R21 NS094488 and NIH/T32 NS082145This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Sumatriptan protects against myocardial ischaemia-reperfusion injury by inhibition of inflammation in rat model.

Ischemic heart disease is a leading cause of death on a global scale, placing major socio-economic burdens on health systems worldwide. Myocardial ischaemia and reperfusion (I/R)-induced tissue injury is associated with alteration in activity of inflammatory system and nitric oxide pathway. Sumatriptan, which is mainly used to relieve migraine headache, has recently been shown to exert anti-inflammatory properties. In this study, we aimed to assess the possible cardioprotective effect of sumatriptan in a rat model of I/R injury. Male Wistar rats were subjected to 30-min ligation of left anterior descending coronary artery and 120-min reperfusion. Animals were randomly divided into five groups: (1) Sham (2) I/R (3) I/R treated with sumatriptan (0.3 mg/kg i.p.) 20min after induction of I/R rats, (4) GR127935 (a selective antagonist of 5-HT1B/D serotonin receptors; 0.3mg/kg) 20min after induction of I/R, and (5) GR127935 (0.3mg/kg) 15min before administration of sumatriptan. Post-infarct treatment with sumatriptan increased left ventricular function, which was damaged in I/R animal's heart. Sumatriptan (0.3mg/kg) decreased lipid peroxidation, CK-MB and lactate dehydrogenase levels; tumor necrosis factor concentration; and Nf-ҡB' protein production. Treatment with sumatriptan significantly increased the endothelial nitric oxide synthase (eNOS) expression consequences nitric oxide metabolites' level in I/R rats. Also, injection of sumatriptan remarkably decreased myocardial tissue injury assessed by histopathological study. These findings suggest that sumatriptan may attenuate I/R injury via modulating the inflammatory responses and endothelial NOS activity. But therapeutic index of sumatriptan is narrow according to the result of this study.