Injection Of Serotonin Research Articles

Embryonic and Larval Development of the Giant ClamTridacna noae(Röding, 1798) (Cardiidae: Tridacninae)

ABSTRACT This paper reports on embryonic and larval development of the giant clam Tridacna noae. Spawning was induced by serotonin injection into the gonad. Unfertilized eggs had a mean (±SE) diameter of 101.14 ± 0.47 µm and spermatozoa heads were 8.92 ± 0.09 µmlong. Embryonic development had progressed to the 8-cell and 16-cell stages by 3 h postfertilization and to the 32-cell stage by 4 h postfertilization. Rotating gastrulae accounted for 82% of developing embryos at 9 h postfertilization. Trochophore larvae accounted for 54% of embryos at 16 h postfertilization, and 98% of larvae at 20 h postfertilization. Straighthinged (D-stage) veligers comprised 74% of developing larvae at 22 h postfertilization with mean (±SE) anteroposterior measurement (APM) of 146.32 ± 0.58 µm, dorsoventral measurement (DVM) of 118.12 ± 0.74 µm, and hinge length of 77.46 ± 0.73 µmat 24 h postfertilization. At 96 h postfertilization, 74% of veligers had settled but had retained the velum without showing development of the foot...

Molecular cloning, expression and functional analysis of three subunits of protein phosphatase 2A (PP2A) from black tiger shrimps (Penaeus monodon).

Protein phosphatase 2A (PP2A) is a cellular serine-threonine (Ser/Thr) phosphatase that plays a crucial role in regulating most cellular functions. In the present study, the full-length cDNAs of three subunits of PmPP2A (PmPP2A-A, PP2A-B and PP2A-C) were cloned from Penaeus monodon, which are the first available for shrimps. Sequence analysis showed that PmPP2A-A, PmPP2A-B and PmPP2A-C encoded polypeptides of 591, 443, and 324 amino acids, respectively. The mRNAs of three subunits of PmPP2A were expressed constitutively in all tissues examined, and predominantly in the ovaries. In ovarian maturation stages, the three subunits of PmPP2A were continuously but differentially expressed. Dopamine and 5-hydroxytryptamine injection experiments were conducted to study the expression profile of three subunits of PmPP2A, and the results indicated that PmPP2A played a negative regulatory role in the process of ovarian maturation. In addition, the recombinant proteins of three subunits of PmPP2A were successfully obtained, and the phosphatase activity of PmPP2A was tested in vitro. The results of this study will advance our understanding about the molecular mechanisms of PmPP2A in Penaeus monodon.

Serotonin Modulation of Premotor Interneuron Excitability in the Snail during Associative Learning

It is shown that after the elaboration of a conditioned reflex in snails, a reliable decrease can be observed in the membrane potential (Vm) of the premotor interneurons at 4 mV, daily injection of serotonin (5-HT) causes a decrease in Vm at 4.5 mV, the same change is observed for Vm in the snails trained after the injection of 5-HT. A single injection of 5-HT causes a depolarization shift of Vm at 5 mV. After the initial stage of training (10–12 pairs) the snails, injected by 5-HT, there is a depolarization at 4.5 mV.

Seasonal variation of sperm quality in Pacific oyster (Crassostrea gigas)

Seasonal changes of sperm quality which can affect sperm biological parameters throughout the breeding period, have been little studied in mollusc species. Controlling gamete quality would aid the management of gametes in hatcheries and the development of selection programs. The aim of the present study was to describe the changes in sperm quality of wild Pacific oysters through the spawning season by comparing sperm parameters at the beginning (May), middle (July) and end (October) of this period using a panel of bio-descriptors. These parameters were studied over the 2014 breeding season based on shed sperm collected after serotonin injection of wild breeders. A significantly higher percentage of motile sperm was observed at the end of the spawning season (+78% relative to the value observed at the beginning) althought a lower total number of spermatozoa was collected (−59%). The mean condition index of oysters, however, was no different between the three sampling dates. For intratesticular sperm, the increase of the percentage of motile sperm and Velocity of the Average Path (VAP) in relation to time post activation was not significantly different among sperm sampling periods, suggesting that the kinetic of the sperm maturation process was similar. Furthermore, the mean VAP observed on shed sperm did not change through the spawning season. The sub-continuous gametogenesis of Pacific oyster can help to explain why only limited consequences of sperm ageing are observed in this species. Furthermore, the effects of sperm ageing may depend on the annual reproductive pattern of Pacific oyster. Statement of relevanceThis study showed the effect of sperm ageing on sperm quality parameters. This knowledge is useful for aquaculture and would support the recent trends of mollusc farming, allowing a better management of the gametes in hatchery.

Characterization, expression and silencing by RNAi of p53 from Penaeus monodon.

The tumor suppressor p53 is a sequence-specific transcription factor, whose target genes can regulate genomic stability, the cellular response to DNA damage and cell-cycle progression. In the present study, the full-length complementary DNA (cDNA) sequence of p53 gene from Penaeus monodon (Pmp53) was cloned by the technology of rapid amplification of cDNA ends (RACE). The cDNA of Pmp53 was 2239bp, encoding a protein of 450 amino acids with calculated molecular weight of 50.62kDa. The temporal expression of Pmp53 in different tissues (ovary, heart, intestine, brain, muscles, stomach and gills) and different developmental stages of ovary was investigated by real-time quantitative PCR (RT-qPCR). The lowest expression level of Pmp53 was observed in the stomach, while the highest expression level was detected in the brain. During the ovary development stages, the expression level of Pmp53 reached the peak at stage III. RNA interference (RNAi) and serotonin (5-hydroxytryptamine, 5-HT) injection experiments were conducted to study the expression profile of Pmp53 and PmCDK2 (cyclin-dependent kinase 2, CDK2). Knocked down of Pmp53 by dsRNA-p53 was sequence-specific and successful. Expression levels of Pmp53 and PmCDK2 in ovary of P. monodon were significantly increased at 12-96h post 5-HT injection. These results indicate that Pmp53 may be involved in the regulation of ovarian development of P. monodon.

Descending serotonergic and noradrenergic systems do not regulate the antipruritic effects of cannabinoids.

For centuries, cannabinoids have been known to be effective in pain states. Itch and pain are two sensations sharing a lot in common. The goal of this research was to observe whether the cannabinoid agonist WIN 55,212-2 reduces serotonin-induced scratching behaviour and whether neurotoxic destruction of descending serotonergic and noradrenergic pathways mediate the antipruritic effect of WIN 55,212-2. Material and methods Scratching behaviour was induced by intradermal injection of serotonin (50 µg/50 µl/mouse) to Balb/c mice. The neurotoxins 5,7-dihydroxytryptamine (5,7-DHT, 50 μg/mouse) and 6-hydroxydopamine (6-OHDA, 20 μg/mouse) are applied intrathecally to deplete serotonin and noradrenaline in the spinal cord. WIN 55,212-2 (1, 3, 10 mg/kg, i.p.) dose-dependently attenuated serotonin-induced scratches. Neurotoxic destruction of neither the serotonergic nor the noradrenergic systems by 5,7-DHT and 6-OHDA, respectively, had any effect on the antipruritic action of WIN 55,212-2. Our findings indicate that cannabinoids dose-dependently reduce serotonin-induced scratching behaviour and neurotoxic destruction of descending inhibitory pathways does not mediate this antipruritic effect.

The quality of great scallop (Pecten maximus) sperm after thawing

Most publications devoted to the cryopreservation of mollusc sperm have focused on the definition of technical protocols, avoiding the description of sperm quality after thawing. The present study investigated the effects of cryopreservation on sperm quality in the great scallop. Wild scallop were fished during the natural spawning period and conditioned in the hatchery before use. Sperm samples were obtained after intragonadal injection of serotonin and cryopreserved using a previously published protocol.Sperm quality was assessed using a panel of four parameters: sperm motility characteristics, using a computer assisted sperm analysis plugin with Image J, intracellular ATP content using an ATP-Lite kit, sperm integrity, using flow cytometry and sperm morphology, using transmission electron microscopy. For each parameter, fresh (control) and thawed spermatozoa were compared.A significant decrease of both the percentage of motile spermatozoa (reduction: 75%) and sperm swimming speed (86%) were observed for thawed sperm compared with fresh sperm. The percentage of living spermatozoa, as assessed using flow cytometry, was significantly lower for thawed sperm (72.4±2.5%) compared with fresh sperm (86.4±1.1). However, no significant difference of intracellular sperm ATP content was observed between fresh and thawed sperm. Post thawing, while some spermatozoa showed little or no morphological differences compared with fresh sperm, others had undergone drastic changes, including swelling of the plasma membrane, structural alterations of the chromatin and damage to mitochondria.In conclusion, the descriptive parameters studied in the present work showed that the quality of thawed great scallop sperm was lower than that of fresh cells but was still sufficient for use in aquaculture programs and sperm cryobanking for this species.

The responses of pulmonary and systemic circulation and airway to anaphylactic mediators in anesthetized BALB/c mice

AimsAnaphylactic shock sometimes accompanies pulmonary vaso- and broncho-constriction. We previously reported the hemodynamic features of mouse anaphylaxis (Life Sci. 2014; 116: 98–105). However, the effects of anaphylactic chemical mediators on the hemodynamics of in vivo mice are not well known. Furthermore, it is uncertain whether the mediators exert the same directional actions. Therefore, we determined their effects systematically on total peripheral resistance (TPR), pulmonary vascular resistance (PVR), or airway pressure (AWP) in anesthetized mice. Main methodsWe measured directly pulmonary arterial pressure, left atrial pressure, systemic arterial pressure, central venous pressure and aortic blood flow to determine PVR and TPR, as well as AWP, following injections of platelet-activating factor (PAF), histamine, serotonin, leukotriene (LT) C4, and prostaglandin (PG) D2 in anesthetized open-chest artificially ventilated BALB/c mice. Key findingsConsecutive administration of any agents increased PVR dose-dependently with the maximal responsiveness being PAF>LTC4>serotonin>>histamine=PGD2. Histamine caused a biphasic PVR response, an initial decrease, which was abolished by L-NAME, followed by an increase at high doses. PAF, serotonin, and histamine decreased TPR dose-dependently, while LTC4 or PGD2 yielded an increase or no change in TPR, respectively. Serotonin, but not the other agents, increased AWP. SignificanceAnaphylactic mediators exert non-uniform actions on the pulmonary and systemic circulation and airway in anesthetized BALB/c mice: PAF, LTC4 and serotonin cause substantial pulmonary vasoconstriction, while histamine biphasic responses of the initial nitric oxide dependent vasodilation followed by vasoconstriction; PAF, serotonin, and histamine, but not LTC4 or PGD2, evoke systemic vasodilatation; only serotonin induces airway constriction.

The Responses of Pulmonary and Systemic Circulation and Airway to Allergic Mediators in Anesthetized Rats.

Lung allergic diseases sometimes accompany pulmonary vaso- and broncho-constriction. Rats are currently used for the experimental study of lung allergies. However, their hemodynamic mechanisms are not fully understood. Therefore the effects of allergic mediators were determined systematically in vivo in rats in terms of pulmonary vascular resistance (PVR), airway pressure (AWP) and total peripheral resistance (TPR). We directly measured pulmonary arterial pressure, left atrial pressure, systemic arterial pressure, central venous pressure and aortic blood flow to determine PVR and TPR, as well as AWP, following injections of platelet-activating factor (PAF), histamine, serotonin, leukotriene (LT) C4, and prostaglandin (PG) D2 in anesthetized open-chest artificially ventilated Sprague-Dawley (SD) rats. PVR was dose-dependently increased by consecutive administration of PAF, LTC4, and PGD2, with the maximal responsiveness being PAF>LTC4>PGD2. However, neither histamine nor serotonin changed PVR. TPR was decreased by all agents except LTC4 which actually increased it. PAF and serotonin, but not the other agents, increased AWP. In conclusion, allergic mediators exert non-uniform actions on pulmonary and systemic circulation and airways in anesthetized SD rats: PAF, LTC4 and PGD2, but not histamine or serotonin, caused substantial pulmonary vasoconstriction; LTC4 yielded systemic vasoconstriction, while the others caused systemic vasodilatation; only two mediators, PAF and serotonin, induce airway constriction.

Molecular cloning and expression analysis of MAT1 gene in black tiger shrimp (Penaeus monodon).

MAT1 (ménage à trois 1), an assembly factor and targeting subunit of the CDK-dependent kinase (CAK), can regulate the cell cycle, transcription, and DNA repair. This study was intended to investigate the role of MAT1 in the reproductive maturation of black tiger shrimp (Penaeus monodon). In this study, the P. monodon MAT1 (PmMAT1) gene was identified and characterized. The full-length cDNA of PmMAT1 was 1490 bp in length with an open-reading frame of 993 bp corresponding to 330 amino acids. The temporal expression of PmMAT1 in various tissues was measured by quantitative real-time PCR with the highest expression observed in ovaries. In the ovaries, the PmMAT1 gene was continuously but differentially expressed during the maturation stages. Comparative analyses of MAT1, CDK7, and cyclin H in the CAK complex of P. monodon indicated that the expression of CDK7 and cyclin H coincided with that of MAT1 during the ovary maturation stages. Serotonin (5-HT) injection promoted the expression level of PmMAT1 in the ovaries of shrimp at 6-48 h post-injection. These results indicate that PmMat1 plays a prominent role in the process of ovarian maturation.

The Effect of Serotonin on Leptin and Grelin Hormones Concentrations in Female Rats

This study was aimed to investigate the relationship of hyperserotoninemia on the adipose tissues performance and satiety status on thirty six female rats. Randomly divided into four groups that individually housed. The first group of six females as a short-term study were given daily serotonin (25 mg/kg) for a week and six controls received saline subcutaneously. Long-term treatment study included 12 females given daily serotonin injections for 3 months vs. 12 controls given saline. The results show significantly decreased in body weights after 7 days and 3 months serotonin injection with mean (200 ± 9.31 g vs. controls 224 ± 11.9 g, p = 0.003 and 234 ± 7.12 g vs. controls 246 ± 14.8 g, p = 0.025 respectively). Plasma leptin were significantly decreased in the rats syringe with serotonin after short-term (133±32.0 vs. controls 208±58.4 pg/ml; p = 0.029) and long-term treatment (172 ± 35.6 vs. controls: 234 ± 60.5 pg/ml; p = 0.007), whereas ghrelin concentrations were unaffected. Consequently, hyperserotoninemia results in low concentrations of plasma leptin with unaffected ghrelin concentrations that may explains a direct serotonin influence on adipose tissues with a significant reduction in body weights of rats vs. controls

Adrenergic β2-receptor mediates itch hypersensitivity following heterotypic chronic stress in rats.

Chronic stress is widely considered to trigger or enhance itch, especially for pruritic dermatitis. However, the molecular mechanisms linking chronic stress and itch are still unknown. The present study aimed to elucidate the role of adrenergic signaling in itch hypersensitivity following heterotypic chronic intermittent stress (HIS) in rats. HIS significantly increased hindlimb scratching, but not forepaw swiping, induced by intradermal injection of 5-hydroxytryptamine (5-HT) in the rat cheek. Coadministration of stress mediators such as norepinephrine or epinephrine dose-dependently increased both 5-HT-induced hindlimb scratching and 5-HT-induced forepaw swiping. HIS-induced itch hypersensitivity was attenuated by blockade of sympathetic signaling through guanethidine treatment, and systemic administration of the β-adrenoceptor antagonist propranolol and the β2-adrenoceptor antagonist butoxamine, but not on treatment with an α-adrenoceptor antagonist phentolamine and a β1-adrenoceptor antagonist atenolol. Moreover, HIS selectively increased the expression of β2-adrenoceptors and proinflammatory factors [tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and nerve growth factor (NGF)] in rat skin. The β-blockers propranolol and butoxamine abolished the upregulation of proinflammatory factors. The β2-adrenoceptor agonist terbutaline was sufficient to enhance the skin expression of TNF-α and IL-1β and to increase 5-HT-induced scratching in naive rats. Pretreatment with TNF-α could increase 5-HT-induced scratching. Together, these results demonstrate that β2-adrenoceptors mediate itch hypersensitivity following chronic stress by inducing proinflammatory factors, such as TNF-α, in the skin.

Modulation of defensive reflex conditioning in snails by serotonin.

Highlights Daily injection of serotonin before a training session accelerated defensive reflex conditioning in snails.Daily injection of 5-hydroxytryptophan before a training session in snails with a deficiency of serotonin induced by the “neurotoxic” analog of serotonin 5,7-dihydroxytryptamine, restored the ability of snails to learn.After injection of the “neurotoxic” analogs of serotonin 5,6- and 5,7-dihydroxytryptamine as well as serotonin, depolarization of the membrane and decrease of the threshold potential of premotor interneurons was observed.We studied the role of serotonin in the mechanisms of learning in terrestrial snails. To produce a serotonin deficit, the “neurotoxic” analogs of serotonin, 5,6- or 5,7-dihydroxytryptamine (5,6/5,7-DHT) were used. Injection of 5,6/5,7-DHT was found to disrupt defensive reflex conditioning. Within 2 weeks of neurotoxin application, the ability to learn had recovered. Daily injection of serotonin before a training session accelerated defensive reflex conditioning and daily injections of 5-HTP in snails with a deficiency of serotonin induced by 5,7-DHT restored the snail's ability to learn. We discovered that injections of the neurotoxins 5,6/5,7-DHT as well as serotonin, caused a decrease in the resting and threshold potentials of the premotor interneurons LPa3 and RPa3.

Serotonin Promotes Development and Regeneration of Spinal Motor Neurons in Zebrafish.

SummaryIn contrast to mammals, zebrafish regenerate spinal motor neurons. During regeneration, developmental signals are re-deployed. Here, we show that, during development, diffuse serotonin promotes spinal motor neuron generation from pMN progenitor cells, leaving interneuron numbers unchanged. Pharmacological manipulations and receptor knockdown indicate that serotonin acts at least in part via 5-HT1A receptors. In adults, serotonin is supplied to the spinal cord mainly (90%) by descending axons from the brain. After a spinal lesion, serotonergic axons degenerate caudal to the lesion but sprout rostral to it. Toxin-mediated ablation of serotonergic axons also rostral to the lesion impaired regeneration of motor neurons only there. Conversely, intraperitoneal serotonin injections doubled numbers of new motor neurons and proliferating pMN-like progenitors caudal to the lesion. Regeneration of spinal-intrinsic serotonergic interneurons was unaltered by these manipulations. Hence, serotonin selectively promotes the development and adult regeneration of motor neurons in zebrafish.

High-dose oral intake of serotonin induces valvular heart disease in rabbits

Carcinoid tumors are rare neuroendocrine malignancies, often originating from enterochromaffin cells in the gastrointestinal tract. They can secrete serotonin (5-hydroxytryptamine, 5-HT), which is largely inactivated by the liver [ [1] Lundin L. Norheim I. Landelius J. Oberg K. Theodorsson-Norheim E. Carcinoid heart disease: relationship of circulating vasoactive substances to ultrasound-detectable cardiac abnormalities. Circulation. 1988; 77: 264-269 Crossref PubMed Scopus (207) Google Scholar ]. Carcinoid heart disease occurs when tumor cells metastasize to the liver, as the vasoactive substances produced are able to reach the systemic circulation via the hepatic vein, causing deposition of fibrous tissue on the endocardial surfaces of the heart [ [2] Ferrans V.J. Roberts W.C. The carcinoid endocardial plaque: an ultrastructural study. Hum. Pathol. 1976; 7: 387-409 Abstract Full Text PDF PubMed Scopus (81) Google Scholar ]. It is predominantly manifested by right-sided valvular heart disease (VHD). Scavenging enzymes in the pulmonary endothelium may explain why left-sided cardiac involvement is unusual [ [3] Chaowalit N. Connolly H.M. Schaff H.V. Webb M.J. Pellikka P.A. Carcinoid heart disease associated with primary ovarian carcinoid tumour. Am. J. Cardiol. 2004; 93: 1314-1315 Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar ]. The severity of cardiac damage is correlated with the plasmatic levels of serotonin, but the low specificity of serotonin for cardiac damage suggests that serotonin may be necessary but not sufficient to induce cardiac lesions [ [4] Robiolio P.A. Rigolin V.H. Wilson J.S. et al. Carcinoid heart disease: correlation of high serotonin levels with valvular abnormalities detected by cardiac catheterization and echocardiography. Circulation. 1995; 92: 790-795 Crossref PubMed Scopus (283) Google Scholar ]. Therefore, other factors combined with serotonin might be required to induce VHD. However, recent animal studies confirmed the development of carcinoid-like valvular deposits in rats after 3 months of daily subcutaneous/intraperitoneal serotonin injections to avoid the liver first-pass clearance [ 5 Gustafsson B. Tommeras K. Nordrum I. et al. Long-term serotonin administration induces heart valve disease in rats. Circulation. 2005; 111: 1517-1522 Crossref PubMed Scopus (198) Google Scholar , 6 Droogmans S. Franken P.R. Garbar C. et al. In vivo model of drug-induced valvular heart disease in rats: pergolide-induced valvular heart disease demonstrated with echocardiography and correlation with pathology. Eur. Heart J. 2007; 28: 2156-2162 Crossref PubMed Scopus (58) Google Scholar ]. Whether oral administration of serotonin can also induce VHD is unknown. We hypothesized that long-term oral serotonin overload in rabbits can lead to VHD, mimicking serotonin-induced lesions of carcinoid heart disease.

5-HT3 receptors antagonists reduce serotonin-induced scratching in mice.

Serotonin (5-hydroxytryptamine, 5-HT) acts as a pruritogen in humans and animals, but the mechanisms of action through that serotonin induces itch response have not been extensively discovered. In our study, we attempted to investigate the role of 5-HT3 receptors in scratching behavior due to intradermal serotonin injection. Intradermal injection of serotonin (14.1-235 nmol/site) into the nape of the neck of mice was performed to elicit itch. Scratching behavior was evaluated by measuring the number of bouts during 60 min after injection. We evaluated the effect of intraperitoneal pretreatment with ondansetron and tropisetron (0.1, 0.3, and 1 mg/kg) on itch induced by serotonin. Also, intradermal ondansetron and tropisetron at doses 50, 100, and 200 nmol/site were concurrently administrated with serotonin. Serotonin produced a significant enhancement in scratching at dose 141 nmol/site. Concurrent administration of ondansetron (50, 100, and 200 nmol/site) and tropisetron (100 and 200 nmol/site) with serotonin reduced scratching activity compared to the animals that only received serotonin. Also, pretreatment with intraperitoneal ondansetron and tropisetron (0.3 and 1 mg/kg) 30 min before serotonin attenuated the itch response. We showed that the scratching induced by intradermal serotonin is mediated by 5-HT3 receptors subtype. It can be concluded that 5-HT3 may play a role in mediating serotonin-associated itch responses, and we introduce 5-HT3 receptors as possible targets for antipruritic agents.

Hemokinin-1-derived peptides have antipruritic effects in rats

Substance P (SP) is a member of the tachykinin peptide family. Hemokinin-1 (HK-1) was recently identified as a new mammalian tachykinin peptide. SP and HK-1 consist of undecapeptides and share a common carboxyl-terminal (C-terminal), Phe-Xaa-Gly-Leu-Met-amide motif, and more varied amino-terminals (N-terminal). The function of SP in the pain system of the spinal cord has been examined in detail, whereas that of HK-1 remains unclear. Therefore, the effects of [Leu 11 ]-HK-1 on the induction of scratching behavior by the intrathecal administration of HK-1 or SP and scratching behavior by a subcutaneous injection of histamine and serotonin were examined in order to elucidate the function of HK-1. The pretreatment with [Leu 11 ]-HK-1 decreased the induction of scratching behavior by HK-1, but not by SP, while the pretreatment with [Leu 11 ]-SP decreased the induction of scratching behavior by SP, but not by HK-1. Furthermore, the pretreatments with [Leu 11 ]-HK-1 and [Leu 11 ]-SP decreased the frequency of scratching following an intradermal injection of pruritogens, such as serotonin (5-HT) and histamine, into the nape of the neck. The effects of the pretreatment with HK-1 (1-5), an N-terminal fragment peptide, were also examined to determine the function of HK-1. The pretreatment with HK-1 (1-5) attenuated the induction of scratching behavior by HK-1 and SP. In addition, the pretreatment with HK-1 (1-5) attenuated the induction of scratching behavior by a subcutaneous injection of histamine and 5-HT, while the pretreatment with SP (1-5) had a negligible effect on the scratching behavior induced by these compounds. Collectively, these results indicated that HK-1 was involved in pruritic processing because the pretreatment with [Leu 11 ]-HK-1 and HK-1 (1-5) attenuated the induction of scratching behavior by an injection of histamine and 5-HT. Peptide-derived antagonists, such as [Leu 11 ]-HK-1 and HK-1 (1-5), may be unsuitable for the treatment of pruritus because of the difficulties associated with penetrating the blood brain barrier. Therefore, the discovery of chemical compounds that function as antagonists to the HK-1-preferred receptor will become more important in the treatment of pruritic diseases.

Involvement of nitric oxide in serotonin-induced scratching in mice.

Serotonin is a pruritogenic substance in humans and animals, but the mechanisms of action through which serotonin induces itch response are not yet understood. To examine the possible role of nitric oxide (NO) in the profile of scratching behaviour due to intradermal injection of serotonin in mice. Intradermal injection of serotonin (14.1-235 nmol per site) into the nape of the neck was used to elicit itch in mice. Scratching behaviour was evaluated by counting the number of bouts during 60 min after injection. To determine the possible involvement of the nitrergic system in serotonin-induced scratching, L-NG-nitroarginine methyl ester [L-NAME; a nonselective nitric oxide synthase (NOS) inhibitor], aminoguanidine [a selective inducible (i)NOS inhibitor] and L-arginine (an NO precursor) were administered intraperitoneally to control and serotonin-injected animals. Intradermal serotonin caused scratching in mice with a bell-shaped dose-response correlation, and the peak effective dose was 141 nmol per site. The majority of scratching bouts in animals occurred 5-10 min after injection. Ineffective doses of L-NAME (3 mg/kg IP) and aminoguanidine (100 mg/kg IP) decreased the scratching induced by intradermal serotonin injection in animals (P < 0.001 and P < 0.001), while an subeffective dose of L-arginine (100 mg/kg IP) augmented the scratching effect of serotonin (P < 0.001). We show for the first time that the scratching induced by intradermal serotonin is mediated by NOS, especially iNOS, activation. We conclude that NO may play a role in mediating itch responses. NO and NOS could be new targets for antipruritic agents.

Evaluation of Caesalpinia bonducella flower extract for anti-inflammatory action in rats and its high performance thin layer chromatography chemical fingerprinting.

Objective:The study is aimed to evaluate anti-inflammatory activity of Caesalpinia bonducella Fleming (Caesalpiniaceae) flower extract (CBFE) and to study its effect on radiographic outcome in adjuvant induced arthritis and authentication by high performance thin layer chromatography (HPTLC) chemical fingerprinting.Materials and Methods:CBFE was administered orally (30, 100, and 300 mg/kg b.wt.) and tested for its anti-inflammatory activity in carrageenan-induced inflammation, cotton pellet induced chronic granulomatous inflammation and autacoids-induced inflammation. Effect on radiographic outcome was tested in adjuvant-induced arthritis. CBFE was HPTLC fingerprinted in suitable solvent system.Result:In carrageenan-induced inflammation, CBFE produced significant inhibition in edema volume at all the doses (30, 100 and 300 mg/kg b.wt.) and percentage of inhibition was 28.68, 31.00, and 22.48, respectively as compared to control at 5 h of its administration. In cotton pellet granuloma assay, CBFE significantly decreased the granuloma weight at 300 mg/kg dose level by 22.53%. CBFE (300 mg/kg) caused significant inhibition by 37.5, 44.44, and 35.29% edema volume, at ½, 1 and 3 h after 5-hydroxytryptamine injection, respectively. Radiographic score of animals treated with 300 mg/kg CBFE was significantly decreased when compared to arthritic control animals.Conclusion:The extract was found to possess significant anti-inflammatory activity. CBFE treatment improved the bony architecture in adjuvant-induced arthritis in rats. The developed HPTLC fingerprint would be helpful in the authentication of C. bonducella flower extract.

Identification of genes associated with reproduction in the Mud Crab (Scylla olivacea) and their differential expression following serotonin stimulation.

The central nervous system (CNS) is often intimately involved in reproduction control and is therefore a target organ for transcriptomic investigations to identify reproduction-associated genes. In this study, 454 transcriptome sequencing was performed on pooled brain and ventral nerve cord of the female mud crab (Scylla olivacea) following serotonin injection (5 µg/g BW). A total of 197,468 sequence reads was obtained with an average length of 828 bp. Approximately 38.7% of 2,183 isotigs matched with significant similarity (E value < 1e−4) to sequences within the Genbank non-redundant (nr) database, with most significant matches being to crustacean and insect sequences. Approximately 32 putative neuropeptide genes were identified from nonmatching blast sequences. In addition, we identified full-length transcripts for crustacean reproductive-related genes, namely farnesoic acid o-methyltransferase (FAMeT), estrogen sulfotransferase (ESULT) and prostaglandin F synthase (PGFS). Following serotonin injection, which would normally initiate reproductive processes, we found up-regulation of FAMeT, ESULT and PGFS expression in the female CNS and ovary. Our data here provides an invaluable new resource for understanding the molecular role of the CNS on reproduction in S. olivacea.