Withdrawal Signs In Morphine-dependent Rats Research Articles

Distinctive roles of L-type calcium channels subtypes within the dorsal hippocampus in formation of morphine withdrawal-induced aversion in rats

Although the negative effects coming along with opiate withdrawal are in part modulated by L-type calcium channels (LTCCs), the distinctive physiological properties and functions of LTCCs subtypes suggest differential roles of subtypes during withdrawal. The present study aimed to examine the contributions of LTCC subtypes, Cav1.2 and Cav1.3, within the dorsal hippocampus (DH) in naloxone-precipitated morphine withdrawal using the conditioned place aversion (CPA) paradigm. Firstly, we injected the non-specific LTCCs antagonist verapamil into the DH of morphine-dependent rats before conditioning an environment with naloxone-precipitated withdrawal. Our results showed that verapamil blocked the acquisition of CPA. Then, to explore the molecular mechanisms of LTCCs subtypes during withdrawal, we measured the protein expression of Cav1.2 and Cav1.3 in morphine-dependent rats under different conditions. In morphine-dependent rats, conditioning with withdrawal increased Cav1.2 expression in the membrane, while only acute naloxone injection increased the membrane expression of Cav1.3. To further determine the causal roles of LTCCs subtypes in the withdrawal process, we used Cav1.2 siRNA or Cav1.3 shRNA to knock down the expression of subtypes and detected the effects on CPA and somatic withdrawal signs in morphine-dependent rats. Cav1.2 siRNA, but not Cav1.3 shRNA, inhibited the acquirement of CPA and relieved somatic withdrawal symptoms. Together, our findings reveal that Cav1.2, but not Cav1.3 plays an important role in mediating morphine withdrawal, suggesting this subtype may serve as a potential therapeutic target for the treatment of negative effects in opiate dependence.

Nicorandil reduces morphine withdrawal symptoms, potentiates morphine antinociception, and ameliorates liver fibrosis in rats

AimsChronic liver disease (CLD) is a serious medical condition affecting patients globally and pain management poses a unique challenge. ATP-sensitive potassium channels (KATP) are expressed in nociceptive neurons and hepatic cells. We tested the hypothesis whether morphine and nicorandil, KATP channel opener, alone and in combination possess hepatoprotective, antinociceptive effect and alter morphine physical dependence. Main methodsIntraperitoneal injection (i.p.) of carbon tetrachloride (CCl4) induced liver fibrosis in male Wistar rats. Nicorandil (15 mg/kg/day) was administered per os for two weeks. Morphine (3.8, 5, 10 mg/kg, i.p.) was administered prior to antinociception testing in tail flick and formalin tests. Morphine physical dependence following naloxone injection, fibrotic, oxidative stress markers, and liver histopathology were assessed. Key findingsMorphine alone, produced insignificant changes of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), hepatic hydroxyproline (Hyp), malondialdehyde (MDA), and superoxide dismutase (SOD) levels and exerted significant antinociception in the pain models. Nicorandil alone protected against liver damage (decreased serum ALT, AST, HA, hepatic Hyp, MDA, increased SOD levels, improved fibrosis scores). Nicorandil/morphine combination produced remarkable hepatoprotection and persistent analgesia compared to morphine alone as evidenced by reduced (EC50) of morphine. Nicorandil augmented morphine analgesia and markedly decreased withdrawal signs in morphine-dependent rats. SignificanceThe data showed for the first time, the hepatoprotection and augmented antinociception mediated by nicorandil/morphine combination in liver fibrosis via antioxidant and antifibrotic mechanisms. Nicorandil ameliorated withdrawal signs in morphine dependence in CLD. Thus, combining nicorandil/morphine provides a novel treatment strategy to ameliorate hepatic injury, potentiate antinociception and overcome morphine-induced physical dependence in liver fibrosis.

Effect of Afghan Ferula assa-foetida L. and Crocus Sativus L. Aqueous Extracts Combination on Withdrawal Signs in Morphine-Dependent Rats

The purpose of this study is to evaluate the effect of Afghan Ferula assa-foetida L. and Crocus Sativus L. aqueous extracts either alone or in combination on morphine withdrawal signs. For this purpose, rats were randomly divided into 13 groups (1 Normal, 1 Morphine, 4 Ferula assa-foetida-treated groups, 4 Crocus sativus-treated groups, and 3 combination groups). Morphine dependency was rendered by subcutaneous injection of morphine hydrochloride for 4 days (10, 20 and 40 mg/kg doses twice daily for 3 days and a single dose of 60 mg/kg on 4th day). Various doses of extracts were injected into extract groups simultaneously with morphine. After two hours of last morphine administration, withdrawal signs were induced by naloxone (3 mg/kg) and noted for 30 minutes. According to the results, different doses of Ferula assa-foetida and Crocus sativus extracts and their combination (in low dose) could significantly decrease the number of morphine withdrawal signs (P<0.05). However, the combination of Ferula assa-foetida and Crocus sativus extracts in high doses showed toxic effects. In conclusion, Ferula assa-foetida and Crocus sativus extract combination in low dose can decrease the morphine withdrawal signs, but without any synergic effects.

Effect of Afghan Ferula assa-foetida L. oleo gum resin aqueous extract on withdrawal signs in morphine-dependent rats

Aim: To investigate the effect of the aqueous extract of Afghan Ferula assa-foetida L. oleo gum resin on the withdrawal signs in morphine-dependent rats. Methods: This study was carried out in 2018. Rats divided into 5 groups (1 Normal Saline, 1 Morphine, and 3 Extract groups). The rats that received morphine and extract became morphine-dependent by subcutaneous (s.c.) administration of morphine hydrochloride for 7 days (2.5, 2.5, 5, 10, 20, 40 mg/kg doses twice daily on 1st to 6th days respectively, and a single dose of 50 mg/kg on 7th day). The extract groups received 50, 75 and 100 mg/kg doses of the Ferula assa-foetida L. oleo gum resin aqueous extract by intraperitoneal (i.p.) administration simultaneously with morphine. Two hours after the administration of the last dose of morphine, Naloxone (3 mg/kg, i.p.) was injected and withdrawal signs were noted for 30 minutes. Results: The results showed that the administration of the Ferula assa-foetida L. oleo gum resin aqueous extract (50, 75 and 100 mg/kg) significantly decreased most of the naloxone induced withdrawal signs in morphine-dependent rats (P

Effect of Afghan Saffron (Crocus sativus L.) Aqueous Extract on Withdrawal Signs in Morphine-Dependent Rats

Introduction: Opioid dependency, as a global problem is accompanied with serious personal, economic, social and hygienic disorders. Synthetic drugs beside their efficacies, have numerous adverse effects. As the medicinal plants have low costs and adverse effects, and they are also affective on different stages of dependency treatment, they attracted the attention of the researchers in the field of medicine. This study was aimed to investigate the effect of the aqueous extract of Afghan saffron on the withdrawal signs in morphine-dependent rats. Methods: Rats divided into 5 groups (1 Normal Saline, 1 Morphine, and 3 Extract groups). The rats that received morphine and extract became morphine-dependent by subcutaneous (s.c.) administration of morphine hydrochloride for 7 days (2.5, 2.5, 5, 10, 20, 40 mg/kg doses twice daily on 1st to 6th days respectively, and a single dose of 50 mg/kg on 7th day). The extract groups received 100, 150 and 200 mg/kg doses of the saffron aqueous extract by intraperitoneal (i.p.) administration simultaneously with morphine. Two hours after the administration of the last dose of morphine, Naloxone (3 mg/kg, i.p.) was injected and withdrawal signs were noted for 30 minutes. Results: The results showed that the administration of the saffron aqueous extract (100, 150 and 200 mg/kg) significantly decreased most of the withdrawal signs in morphine-dependent rats (P<0.05). Conclusion: Afghan saffron aqueous extract can alleviate the withdrawal signs in morphine-dependent rats.

Pharmacologic effects of naldemedine, a peripherally acting μ-opioid receptor antagonist, in in vitro and in vivo models of opioid-induced constipation.

BackgroundNaldemedine (S‐297995) is a peripherally acting μ‐opioid receptor antagonist developed as a once‐daily oral drug for opioid‐induced constipation (OIC) in adults with chronic noncancer or cancer pain. This study characterized the pharmacological effects of naldemedine in vitro and in vivo.MethodsThe binding affinity and antagonist activity of naldemedine against recombinant human μ‐, δ‐, and κ‐opioid receptors were assayed in vitro. Pharmacologic effects of naldemedine were investigated using animal models of morphine‐induced inhibition of small and large intestinal transit, castor oil‐induced diarrhea, antinociception, and morphine withdrawal.Key ResultsNaldemedine showed potent binding affinity and antagonist activities for recombinant human μ‐, δ‐, and κ‐opioid receptors. Naldemedine significantly reduced opioid‐induced inhibition of small intestinal transit (0.03‐10 mg kg−1; P < 0.05) and large intestinal transit (0.3‐1 μmol L−1; P < 0.05). Naldemedine (0.03‐1 mg kg−1) pretreatment significantly reversed the inhibition of castor oil‐induced diarrhea by subcutaneous morphine (P < 0.01). Naldemedine (1‐30 mg kg−1) pretreatment (1 or 2 hours) did not alter the analgesic effects of morphine in a model measuring the latency of a rat to flick its tail following thermal stimulation. However, a significant delayed reduction of the analgesic effect of morphine was seen with higher doses of naldemedine (10‐30 mg kg−1). Some centrally mediated and peripherally mediated withdrawal signs in morphine‐dependent rats were seen with naldemedine doses ≥3 and ≥0.3 mg kg−1, respectively.Conclusions & InferencesNaldemedine displayed potent binding affinity to, and antagonistic activity against, μ‐, δ‐, and κ‐opioid receptors. Naldemedine tempered OIC in vivo without compromising opioid analgesia.

Anatomically dissociable effects of dopamine D1 receptor agonists on reward and relief of withdrawal in morphine-dependent rats.

Chronic opiate administration induces neuroadaptations within the nucleus accumbens (NAc) and ventral tegmental area (VTA) that can contribute to dependence. We have shown that morphine dependence shifts the behavioral consequences of D1 dopamine (DA) receptor signaling: systemic administration of a D1 receptor agonist is rewarding and blocks naloxone-precipitated withdrawal signs in morphine-dependent rats, but has minimal effects in nondependent rats. These data suggest that D1 receptors acquire the ability to regulate reward and withdrawal in morphine-dependent rats. The brain regions involved in these effects are not known. Studies were designed to test the hypothesis that the nucleus accumbens shell (NASh) and the ventral tegmental area (VTA) are important sites for mediating the behavioral effects of D1 receptor activation in morphine-dependent rats. The effects of microinjecting the D1 receptor agonist SKF 82958 into the NASh or the VTA on place conditioning and somatic withdrawal signs were studied in morphine-dependent and nondependent rats. Intra-NASh microinjection of SKF 82958 (1 microg/side) established conditioned place preferences in morphine-dependent but not nondependent rats, but had no effect on naloxone-induced place aversions or somatic withdrawal signs. Intra-VTA microinjection of SKF 82958 (2 microg) did not establish place preferences under any conditions, but blocked naloxone-induced place aversions without effects on somatic withdrawal signs. There is an anatomical dissociation between D1 receptor-mediated reward and relief of withdrawal in morphine-dependent rats. When combined, the individual effects of D1 receptor activation in the NASh and VTA on the affective signs of precipitated morphine withdrawal resemble those seen with systemic administration.

Attenuation of morphine withdrawal signs by low level laser therapy in rats

In the present study, the effects of low-intensity laser therapy (LILT) on naloxone-induced withdrawal signs of morphine-dependent rats were examined. Low-intensity lasers with a power density of 12.5 J/cm 2 have been used by a Ga–Al–As laser. One-way ANOVA showed that the LILT which applied immediately or 15 min prior to naloxone injection significantly decreased total withdrawal score (TWS). These results suggest that LILT prior to naloxone injection attenuates the expression of withdrawal signs in morphine-dependent rats. Further studies may elucidate the likely role of LILT in clinical management of opioid withdrawal syndrome.

Attenuation of morphine withdrawal signs by the GABA B receptor agonist baclofen

The present study examined the effect of the γ-aminobutyric acid B (GABA B) receptor agonist, baclofen on naloxone-induced withdrawal signs in morphine-dependent rats and modification by the antagonist, 3-aminopropyl-cyclohexylmethylphosphinic acid (CGP 46381). Morphine was administered via mini-osmotic pumps for 7 days to induce physical dependence. Baclofen (20 mg kg −1) decreased stereotyped head movements, chewing, chatter, ptosis and body weight loss, induced by naloxone (10 mg kg −1) in morphine-dependent rats. CGP 46381 (20 mg kg −1) reversed the effects exerted by baclofen on stereotyped head movements, ptosis, and weight loss and partially reversed the effect of baclofen on chewing. It can be concluded that baclofen has some potential in the treatment of opioid withdrawal and that GABA B receptors may be implicated in such a withdrawal.

Caffeine increases paragigantocellularis neuronal firing rate and induces withdrawal signs in morphine-dependent rats

Using single unit recording in nucleus paragigantocellularis neurons located in the rostral ventrolateral medulla, and measuring the precipitated withdrawal syndrome, we investigated whether chronic morphine administration would produce adaptive changes in the adenosine system. Caffeine (50 mg/kg, i.p.) induced withdrawal signs (head shakes, tooth chattering, ejaculation, chewing, and irritability) in morphine-dependent rats 10–18 min after the injection. Only the tooth chattering and diarrhea were expressed following a direct paragigantocellularis injection of caffeine (200 μM, 0.5 μl). The spontaneous activity of paragigantocellularis neurons was significantly decreased by microinjection of both adenosine (10 nM) and an adenosine A 1 receptor-selective agonist, cyclohexyladenosine (200 μM), into the paragigantocellularis nucleus of both control and morphine-dependent rats, but the decrease in firing rate of paragigantocellularis neurons of morphine-dependent rats was greater than that of control ones. There was also a significant enhancement of spontaneous activity of paragigantocellularis neurons 8–15 min after caffeine administration (50 mg/kg, i.p.) and 10–18 min after the injection of an adenosine A 1 receptor-selective antagonist 8-phenyltheophylline (10 mg/kg, i.p.) in both control and morphine-dependent rats. However, the effect of the antagonists was greater in morphine-dependent rats than in control ones. These data suggest that there is an increase in the sensitivity of nucleus paragigantocellularis neurons to adenosine receptor ligands in morphine-dependent rats that may be associated with the ability of caffeine to produce withdrawal signs.

Chronomodulation of Withdrawal Signs in Morphine-Dependent Rats

Male Sprague-Dawley rats (200–250 g) were segregated into 12 groups (n =5). Six groups were injected with morphine sulphate (10,20,30,50 mg/kg,ip) on days 1, 2, 3 and 4 respectively. The specified dose of morphine was given in two divided doses daily at 1000 h (light) and 2200 h (dark) for four consecutive days. The remaining six groups received saline. On day 5, the rats from saline and morphine treated groups were injected with naloxone (50 mg/kg, ip) at 0600 h, 1000 h, 1400 h, 1800 h, 2200 h, or 0200 h to precipitate the withdrawal signs during the light and dark phases of the 24 h period. Withdrawal signs were monitored for the following 30 min. Diarrhea, tremor, teeth chattering and crying (vocalization) were exhibited exclusively by the morphine-dependent rats. Escape attempts and restless activity were observed mostly in morphine-dependent groups, except for a limited response by controls at 0200 h or 0600 h. The percentage response of other signs such as hunch-back posture, piloerection, stereotypic jumping, urination and salivation in morphine-treated groups was significantly higher than controls (p <0.05). Manifestation of these signs of morphine withdrawal over a 24 h light–dark cycle is addressed.

Repeated naltrexone administration accelerates resolution of morphine somatic withdrawal signs in morphine-dependent rats

Morphine-dependent rats were divided into two subgroups. The first was allowed to develop a spontaneous withdrawal syndrome which was still present 33 h after the last morphine administration. The second subgroup received five injections of naltrexone. While the first two injections of naltrexone precipitated a marked somatic withdrawal syndrome, subsequent naltrexone failed to worsen the somatic signs. 24 h after the last morphine administration, naltrexone was completely ineffective. It is concluded that naltrexone shortens the duration of the morphine somatic withdrawal signs in dependent rats.

High affinity ibogaine binding to a mu opioid agonist site

The naturally occurring indole alkaloid ibogaine is of interest because of its reported ability to block drug seeking behavior for extended periods. The compound also potentiates morphine-induced analgesia in mice and reduces certain naltrexone-precipitated withdrawal signs in morphine-dependent rats. Although these results might suggest ibogaine interaction with opioid receptors, previous receptor binding studies (Brain Res. 571:242–247, 1980) found that ibogaine had a K i value of only 2 μM for the kappa opioid receptor and was virtually inactive in blocking mu and delta receptor binding ( K i >100 μM). The present investigation of ibogaine interaction with the mu opioid receptor from mouse forebrain labeled with [3H]-naloxone, however, yielded significantly more potent mu opioid K i values. LIGAND analysis indicated that the data were best fit by a two site binding model, with K i values of about 130 nM and 4 μM, reflecting ibogaine recognition of different agonist affinity states of the receptor. Inclusion of 100 mM NaCl in the assay to induce the agonist low affinity state of the receptor, reduced ibogaine's inhibition of [ 3H]-naloxone binding. These results suggest that ibogaine is an agonist at the mu opioid receptor with a K i value of about 130 nM, potentially explaining ibogaine's antinociceptive effects as well as its reported reduction of opioid withdrawal symptoms and attenuation of drug seeking behavior.

Endogenous κ-opioid systems in opiate withdrawal: role in aversion and accompanying changes in mesolimbic dopamine release

The kappa-opioid receptor antagonist nor-binaltorphimine (nor-BNI) was recently shown to potentiate certain overt withdrawal signs in morphine-dependent rats. The present study sought to further assess this phenomenon by examining the influence of nor-BNI treatment upon the conditioned place aversion associated with the naloxone-precipitated withdrawal syndrome. In addition, in vivo microdialysis studies were conducted in morphine-dependent rats to determine whether nor-BNI treatment can modify withdrawal-induced changes in basal dopamine (DA) release within the mesolimbic system. Rats were pretreated with either saline or a single dose of nor-BNI and then received ascending doses of morphine for 10 days. A withdrawal syndrome was then precipitated by the administration of naloxone (1 mg/kg SC). In rats which received chronic morphine injections, administration of naloxone produced a characteristic withdrawal syndrome and a marked aversion for an environment previously associated with naloxone-precipitated withdrawal. Nor-BNI treatment potentiated most overt signs of physical dependence. This treatment also resulted in a greater withdrawal-induced place aversion. Morphine-dependent rats exhibited a marked reduction in basal mesolimbic DA release. An even greater decrease in basal DA release was observed in nor-BNI treated rats. These results suggest that endogenous kappa-systems are important in the modulation of mesolimbic DA release and the accompanying place aversion which occurs during opiate withdrawal.

Effect of adenosine analogues on the expression of opiate withdrawal in rats

The aim of this study was to test whether convergent dependence occurs in vivo. The adenosine A 1 receptor agonist N 6-[( R)]-1-methyl-2-phenylethyl]adenosine, (R-PIA), the A 2 agonist 2-(phenylamino)adenosine (CV-1808), the nonselective A 1, A 2 agonist (adenosine-5′-ethylcarboxamide (NECA), and the α 2-adrenoceptor agonist clonidine were screened (each at 30, 100, and 300 μg/kg, SC) for their ability to alter naloxine-precipitated withdrawal signs in morphine-dependent rats. The results indicate that there is convergent dependence involving opioid and adenosine A 1 receptors on those effects expressed by withdrawal diarrhoea, paw-shakes, teeth-chattering, body-shakes, and jumping. Further, dependence expressed by body-shakes involves convergence involving A 1 receptors, as well as α 2-adrenoceptors; while A 1 receptors are involved in dependence expressed by jumping, stimulation of α 2-adrenoceptors augments this signs. Adenosine analogues may be of clinical value for detoxification of opiate addicts.

Effects of ibogaine on acute signs of morphine withdrawal in rats: Independence from tremor

Because of the claim that ibogaine suppresses the symptoms of “narcotic withdrawal” in humans, the effect of ibogaine on naltrexone-precipitated withdrawal signs in morphine-dependent rats was assessed. Morphine was administered subcutaneously through implanted silicone reservoirs for 5 days. Ibogaine (20, 40 or 80 mg/kg, i.p.) or saline was administered 30 min prior to challenge with naltrexone (1 mg/kg, i.p.) and withdrawal signs were counted for the following 2 hr. Ibogaine (40 and 80 mg/kg) significantly reduced the occurrence of four signs (wet-dog shakes, grooming, teeth chattering and diarrhea) during naltrexone-precipitated withdrawal; three other signs (weight loss, burying and flinching) were unaffected. Ibogaine induces head and body tremors lasting for 2–3 hr and the tremors might have interfered with the expression of opioid withdrawal. To examine this issue, another experiment was conducted in which ibogaine (40 mg/kg) or saline was administered 4 hr prior to challenge with naltrexone. Although there was a complete absence of tremors, ibogaine still significantly reduced the occurrence of the same four signs of withdrawal.

Physical Dependence Potential of an Enkephalin Analog, EK-399, in Rats

The physical dependence potential of Tyr-D-Met(0)-GIy-EtPhe-NHNHCOCH3-AcOH (EK-399), a novel enkephalin analog with a potent analgesic effect, was assessed in rats. The animals were given EK-399 (0.008, 0.032, 0.125, or 0.5 mg/kg), morphine (0.125, 0.5, or 2 mg/kg), pethidine (2 or 8 mg/kg), or pentazocine (2 or 8 mg/kg) every hour through an implanted intravenous cannula. After 3 days of treatment, precipitated withdrawal tests were conducted: naloxone (5 mg/kg) was administered subcutaneously. Rats treated with morphine showed withdrawal signs such as hyperirritability, salivation, diarrhea, and weight loss. Rats treated with pethidine, pentazocine, or EK-399 showed similar signs, but they were less evident than those in morphine-treated rats. In abrupt withdrawal tests after 7 days of treatment, rats treated with morphine, pethidine, or pentazocine showed weight loss, whereas rats treated with EK-399 showed little or no weight loss. In substitution tests, EK-399 suppressed the withdrawal signs in morphine-dependent rats, and vice versa. These results show that EK-399 has a morphine-like physical dependence potential that is weaker than that of morphine, pethidine, or pentazocine in rats.

Analgesic and other pharmacological activities of an enkephalin analogue, syndyphalin (SD)-25

The pharmacological actions of Tyr-D-Met(O)-Gly-MePheol (syndyphalin (SD)-25) were compared with those of morphine after systematic administration. The analgesic potency of SD-25 was about 4 times that of morphine when administered s.c. to rats. SD-25 did not exhibit any narcotic antagonist activity. Subcutaneous administration of SD-25 produced a dose-dependent suppression of morphine withdrawal signs in morphine-dependent rats, typical morphine-like jumping in the mouse jumping test, and an increase in spontaneous locomotor activity in mice. These activities were 2–5 times those of morphine. In the anaesthetized dog, intravenous administration of SD-25 produced a 100–1000 times stronger increase in the amplitude of contractions of the jejunum than did morphine, a weaker depression in respiration than morphine, and a slight increase in blood pressure. These effects were reversed by naloxone. These results indicate that SD-25 possesses potent central nervous system actions closely similar to those of morphine, but its effect on blood pressure and respiration was weaker than that of morphine.