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Abstract Background Medications currently recommended for the treatment of Obsessive-Compulsive Disorder (OCD) usually relieve the severity of symptoms by as much as 20–30%, and satisfactory treatment is obtained in 40–60% of patients with OCD. Nevertheless, the remaining symptoms continue to impair the patients’ function. Therefore, it is necessary to investigate possible strategies to improve the mitigation of symptoms. In this study, the main objective was to examine and investigate the effectiveness of granisetron, which is a serotonin 5-hydroxytryptamine receptor type 3 (5-HT3) antagonist, as an adjunct therapy to selective serotonin reuptake inhibitors, for the purpose of ameliorating OCD symptoms. Methods fifty-eight patients diagnosed with OCD, based on Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria, who had a Yale-Brown obsessive-compulsive scale (Y-BOCS) score of more than 21 were recruited in a double-blinded, parallel-group, placebo-controlled, clinical trial of 10 weeks to receive either granisetron (1 mg twice daily) and sertraline (100 mg daily initially followed by 200 mg daily after week 4) or placebo and sertraline. The primary outcome was OCD symptoms measured by the Y-BOCS. Results Y-BOCS total score significantly dropped in both groups (28.9 to 17.7 for granisetron plus sertraline and 27.5 to 19.3 for placebo plus sertraline group with a slightly greater drop for granisetron plus sertraline group), while the granisetron plus sertraline group experienced a significantly greater reduction in obsession scores (Greenhouse-Geisser F(2.32,97.57) = 4.52,p-value = 0.01). Moreover, in comparison with the placebo plus sertraline group, the proportion of the patients showing complete response was considerably higher among the granisetron plus sertraline group (P-value

Background: Medications currently recommended for the treatment of Obsessive-Compulsive Disorder (OCD) usually relieve the severity of symptoms by as much as 20–30%, and satisfactory treatment is obtained in 40–60% of patients with OCD. Nevertheless, the remaining symptoms continue to impair the patients' function. Therefore, it is necessary to investigate possible strategies to improve the mitigation of symptoms. In this study, the main objective was to examine and investigate the effectiveness of granisetron, which is a serotonin 5-hydroxytryptamine receptor type 3 (5-HT3) antagonist, as an adjunct therapy to selective serotonin reuptake inhibitors, for the purpose of ameliorating OCD symptoms. Methods: fifty-eight patients diagnosed with OCD, based on Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria, who had a Yale-Brown obsessive-compulsive scale (Y-BOCS) score of more than 21 were recruited in a double-blinded, parallel-group, placebo-controlled, clinical trial of 10 weeks to receive either granisetron (1 mg twice daily) and sertraline (100 mg daily initially followed by 200 mg daily after week 4) or placebo and sertraline. The primary outcome was OCD symptoms measured by the Y-BOCS. Results: Y-BOCS total score significantly dropped in both groups (28.9 to 17.7 for granisetron plus sertraline and 27.5 to 19.3 for placebo plus sertraline group with a slightly greater drop for granisetron plus sertraline group), while the granisetron plus sertraline group experienced a significantly greater reduction in obsession scores (Greenhouse-Geisser F(2.32,97.57) = 4.52,p-value = 0.01). Moreover, in comparison with the placebo plus sertraline group, the proportion of the patients showing complete response was considerably higher among the granisetron plus sertraline group (P-value < 0.01). No major adverse effects were observed in any of the groups. Conclusion: The results suggest that granisetron augmentation of sertraline may increase the rate of response in patients with moderate to severe non-refractory OCD. Further studies are suggested in this regard. [ABSTRACT FROM AUTHOR]

Background: About 50% of obsessive-compulsive disorder patients still suffer significant symptoms even after the recommended first-line therapy. This demonstrates the necessity to investigate strategies to improve alleviation of symptoms.Objective: The main objective of this study was to investigate the efficacy of a 5-hydroxytryptophan 3 receptor antagonist, tropisetron, as an adjuvant therapy to selective serotonin reuptake inhibitors, in ameliorating obsessive-compulsive disorder symptoms.Methods: Men and women between the ages of 18-60 years diagnosed with obsessive-compulsive disorder, based on DSM5, who had a Yale-Brown obsessive compulsive scale score of more than 21 were recruited in a double-blinded, parallel-group, placebo-controlled, clinical trial of 10 weeks to receive either tropisetron (5 mg twice daily) and fluvoxamine (100 mg daily initially followed by 200 mg daily after week 4) or placebo and fluvoxamine. The primary outcome of interest in this study was the Yale-Brown obsessive compulsive scale total score decrease from baseline.Results: One hundred and eight participants were equally randomized into two groups; 48 participants in each group finished the trial. The Yale-Brown obsessive compulsive total score significantly dropped in both groups while the tropisetron group participants experienced a significantly higher decrease in their scores (Greenhouse-Geisser F(1.53-65.87)=3.516, p-value=0.04). No major adverse effect was observed in any of the groups.Conclusion: This trial showed a significant efficacy for tropisetron over placebo in treatment of obsessive-compulsive disorder symptoms when added to fluvoxamine. [ABSTRACT FROM AUTHOR]

Abstract: Irritable bowel syndrome (IBS) and functional dyspepsia (FD) are both functional gastrointestinal disorders and frequently co-occur in patients. While one cause of FD appears to be gastric hypersensitivity, whether the hypersensitivity is affected by IBS treatments remains unclear, given the lack of appropriate animal models for testing. Here, we established an experimental model of duodenal acidification-induced gastric hypersensitivity in conscious rats. The model involved duodenal acidification induced by the infusion of hydrochloric acid into the proximal duodenum, with the nociceptive response being determined as the change in mean arterial pressure (MAP) during gastric distension via an indwelling latex balloon. Using our model we evaluated the effects of duodenal acidification, increased distension pressure, and orally administered therapeutic agents for IBS with diarrhea (IBS-D). Duodenal acidification enhanced the pressor response during gastric distension, and pretreatment with the opioid κ-receptor agonist fedotozine (10mg/kg, intra-arterial) inhibited the pressor response. Pressure levels of 15–60mmHg increased MAP in response to gastric distension. The serotonin 5-HT3 receptor antagonist ramosetron (30μg/kg) inhibited MAP increase induced by duodenal acidification, with no other IBS-D therapeutic agents showing any effect. In contrast, the serotonin 5-HT3 receptor agonist m-chlorophenylbiguanide (1mg/kg) significantly enhanced the pressor response during gastric distension. These findings indicate that the serotonin 5-HT3 receptor plays a key role in duodenal acidification-induced gastric hypersensitivity in rats, suggesting that ramosetron may reduce FD symptoms by ameliorating sensitized gastric perception. [Copyright &y& Elsevier]

Introduction:The study objective was to determine the effect of central noradrenergic system lesions performed in the early extrafetal life period on dopamine synthesis in the rat brain. The content of L-dihydroxyphenylalanine (L-DOPA) was assessed in the frontal lobe, thalamus, hypothalamus and brain stem of rats by high-pressure chromatography with electrochemical detection (HPLC/ED) after administration of 5-HT3 receptor ligands. Material and Methods:Adult male Wistar rats which underwent central noradrenergic lesions by DSP-4 administration (50 mg/kg m.c. i.p.) on day 1 and 3 of life received i.p. injections of the aromatic amino acid decarboxylase inhibitor (NSD-1050) in a dose of 100 mg/kg b.w. Next, 30 min after NSD-1050 injection, the animals were decapitated by guillotine. Selected brain structures were dissected and L-DOPA content was determined by HPLC/ED. Results and Conclusions:A statistically significant reduction was found in DA synthesis in the group of animals with DSP-4 lesions induced by PBG (1-phenylbiguanide, 7.5 mg/kg b.w. i.p.) and ondansetron (1.0 mg/kg b.w. i.p.). Morphine and PBG had no major effect on DA synthesis in the cerebral cortex of both control animals and in rats with noradrenergic lesions. The assessment of the effect of DSP-4 lesions on L-DOPA content in the brain stem after administration of morphine (7.5 mg/kg b.w. s.c.), PBG (7.5 mg/kg b.w. i.p.) or ondansetron (1.0 mg/kg b.w. i.p.) separately or jointly showed a statistically significant increase in the synthesis of DA in animals with DSP-4 lesions, as compared to the control group exposed to 0.9% NaCl and morphine. The analysis of the effect of DSP-4 lesions on L-DOPA content in the thalamus and hypothalamus revealed no statistically significant differences between the control groups of rats and those with DSP-4 lesions. As shown by this model, permanent noradrenergic lesions in animals in the early extra-fetal period result in increased reactivity of the central dopamine system [ABSTRACT FROM AUTHOR]

Abstract: Cholecystokinin and serotonin are released from the gastrointestinal tract in response to the products of digestion and play critical roles in mediating pancreatic secretion via vago-vagal reflex pathways. This study was designed to investigate the effects of activation of cholecystokinin CCK1 and serotonin (5-hydroxytryptamine, 5-HT) 5-HT3 receptors on pancreatic vagal afferent discharge and to determine whether there is an interaction between these receptors. Male Sprague Dawley rats anaesthetised with isoflurane (1.5%/100% O2) were used in all experiments. The effects of systemic administration of cholecystokinin and the serotonin 5-HT3 receptor agonist phenylbiguanide on pancreatic vagal afferent discharge were recorded before and after administration of cholecystokinin CCK1 and serotonin 5-HT3 receptor antagonists. Cholecystokinin (0.1–10 µg/kg, i.v.) and phenylbiguanide (1 and 10 µg/kg, i.v.) increased pancreatic vagal afferent discharge dose-dependently. Cholecystokinin CCK1 receptor antagonists, lorglumide (10 mg/kg, i.v.) and devazepide (0.5 mg/kg, i.v.), reduced cholecystokinin- and phenylbiguanide-induced increases in pancreatic vagal afferent discharge significantly (n =5, P <0.05). On the other hand, serotonin 5-HT3 receptor blockade with granisetron (1 mg/kg, i.v.) or MDL72222 ([(1S,5R)-8-methyl-8-azabicyclo[3.2.1]octan-3-yl] 3,5-dichlorobenzoate; 0.1 mg/kg, i.v.) inhibited the pancreatic vagal afferent discharge responses to phenylbiguanide but not those to cholecystokinin. This study has confirmed that cholecystokinin and phenylbiguanide activate pancreatic vagal afferent discharge via activation of cholecystokinin CCK1 and serotonin 5-HT3 receptors, respectively. In addition, it has demonstrated that (i) the serotonin 5-HT3 agonist phenylbiguanide acts partly via an interaction with cholecystokinin CCK1 receptors, and (ii) the actions of cholecystokinin are not dependent on serotonin 5-HT3 receptor activation. [Copyright &y& Elsevier]

The expression of the 5-HT3 receptor, a member of the serotonin receptor family, was examined in rat cerebellum of saline- or cocaine-treated rats. Both immunohistochemistry and Western blot analysis were used. We found that the expression of this serotonin receptor subtype was increased in the cerebellum of rats injected either acutely or repeatedly (1 injection/day for 10 days) with cocaine. The stimulation was more pronounced after a single injection than after a series of 10 injections. Surprisingly, the expression of the 5-HT3 receptor was mainly localized in Bergmann glial cells, as assessed from the co-localization of the receptor with the glial cell marker glial fibrillary acidic protein (GFAP). Our data emphasize the importance of the 5-HT3 receptor induction in the cerebellum as part of the neuroadaptations taking place in rat brain in response to the psychostimulant cocaine. [ABSTRACT FROM AUTHOR]