1. 5-HT inhibits spontaneous fluid secretion as well as stimulated secretion with secretin (cAMP mediated) or ACh (Ca2+ mediated) in the isolated guinea pig pancreatic ducts. 2. The inhibitory effect of 5-HT is reversible and is dependent on the concentration in the range 0.01-0.1 microM, which is much lower than those that affect intestinal motility and secretion. 3. The 5-HT3 receptor in duct cells appears to mediate the inhibitory effect of 5-HT. 4. [Ca2+]i is unlikely to mediate the inhibitory effect of 5-HT.
5-Methoxytryptamine/pharmacology ; Acetylcholine/pharmacology ; Animal ; Calcium/metabolism ; Guinea Pigs ; Pancreatic Ducts/metabolism* ; Pancreatic Ducts/drug effects ; Secretin/pharmacology ; Serotonin/pharmacology ; Serotonin/metabolism* ; Serotonin/analogs & derivatives* ; Vasodilator Agents/pharmacology

No abstract available.
Humans ; Serotonin*

No abstract available.
Colon* ; Humans ; Serotonin*

Mosapride accelerates gastric emptying by acting on 5-hydroxytryptamine type 4 (5-HT₄) receptor and is frequently used in the treatment of gastrointestinal (GI) disorders requiring gastroprokinetic efficacy. We tested the effect of mosapride on 5-hydroxytryptamine type 3 (5-HT₃) receptor currents because the 5-HT₃ receptors are also known to be expressed in the GI system and have an important role in the regulation of GI functions. Using the whole-cell voltage clamp method, we compared the currents of the 5-HT₃ receptors when 5-HT was applied alone or was co-applied with mosapride in cultured NCB-20 cells known to express 5-HT₃ receptors. The 5-HT₃ receptor current amplitudes were inhibited by mosapride in a concentration-dependent manner. Mosapride blocked the peak currents evoked by the application of 5-HT in a competitive manner because the EC₅₀ shifted to the right without changing the maximal effect. The rise slopes of 5-HT₃ receptor currents were decreased by mosapride. Pre-application of mosapride before co-application, augmented the inhibitory effect of mosapride, which suggests a closed channel blocking mechanism. Mosapride also blocked the opened 5-HT₃ receptor because it inhibited the 5-HT₃ receptor current in the middle of the application of 5-HT. It accelerated desensitization of the 5-HT₃ receptor but did not change the recovery process from the receptor desensitization. There were no voltage-, or use-dependency in its blocking effects. These results suggest that mosapride inhibited the 5-HT₃ receptor through a competitive blocking mechanism probably by binding to the receptor in closed state, which could be involved in the pharmacological effects of mosapride to treat GI disorders.
Gastric Emptying ; Methods ; Serotonin

There is no doubt that dopamine plays a critical role in the etiopathogenesis of schizophrenia. However, there appeared some limitations in explaining the complex phenomena of schizophrenia. Recent research data suggest that dysfunction in serotonergic system may be involved Before the dopamine hypothesis of schizophrenia became established, the interest in serotonin(5-ydroxytryptamine, 5-HT) as an etiological substrate of this illness occurred. Recently the importance and extent of 5-HT's involvement in the pathophysiology and mechanism of action of antipsychotic drug is actively investigated. In recent years, therapeutic success of clozapine and risperidones has increased attention on the interaction between the 5-HT and dopamine systems in schizophrenia. This led to the serotonin-dopamine for antipsychotic. The authors review the evidence for the role of 5-HT in schizophrenia and serotonin-dopamine interaction.
Clozapine ; Dopamine ; Schizophrenia* ; Serotonin*

The mirtazapine is a relatively new antidepressant that has noradrenergic and specific serotonin antagonist action(NaSSAs). This has been known as one of the most safest drugs because of its few side effects. Until now, there have been only one case report that mirtazapine causes a EPS side effect(restless leg syndrome). But the peculiar mechanism of this drug makes it impossible to explain the exact reasons why the mirtazapine could induce EPS symptoms. Authors obseved three cases of mirtazapine indeced akathisia. We could not explain the phenomenon the other way except akathisia. So here we presents the three case of mirtazapine induced akathisia and a few possible hypothesis of this phenomenon.
Leg ; Psychomotor Agitation* ; Serotonin

Humans ; Serotonin ; Cardiovascular Diseases

OBJECTIVE: Selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), and noradrenergic and specific serotonergic antidepressant (NaSSA) are extensively used to treat the patients with depression. Although depressed patients are complaining of somatic pain as a complication of depression, there has not been any straight-forward comparative data of the effect of SSRIs, SNRIs, and NaSSA on pain. Therefore, in this study, we tried to figure out the effect of each drug i.e.SSRIs, SNRIs, and NaSSA, on pain by administrating each drug to three different groups of patient with depression. METHODS: We conducted a chart review of patients, who visited a university hospital. From January, 2010 to February, 2012, total 150 inpatients who had been diagnosed as major depression by Diagnostic and Statistical Manual of Mental Disorders-4th edition criteria, and administered any of three drugs [SSRIs (n=50), SNRIs (n=50), and NaSSA (n=50)] at least for fore weeks in the department of psychiatry in Chung-Ang University Hospital, were enrolled for this study. We compared and analyzed depressive symptoms and pain between three groups. Depressive symptoms and pain were evaluated by Korean version of the Hamilton Depression Rating Scale and visual analogue scale at baseline and fore weeks later. RESULTS: There was no difference in the age, gender, severity of depression and pain among three groups. However, there was difference in 50% depressive symptomatic improvement rate in the following four weeks among three groups. The number of patient found to achieve 50% symptomatic improvement in SSRIs, SNRIs, and NaSSA group was 17 (34%), 20 (40%), and 34 (54%) in each group, respectively, indicating significantly higher improvement rate in NaSSA compared to SSRIs. During four weeks of administration period, significant difference in 50% pain improvement rate was observed among three groups. The number of patient found to achieve 50% pain improvement in SSRIs, SNRIs, and NaSSA group was 14 (28%), 20 (40%), and 27 (54%) in each group, respectively, showing twice higher pain improvement rate in NaSSA compared to SSRIs. CONCLUSION: This result indicates better efficacy of NaSSA on pain improvement compared to SSRIs, and SNRIs in depressed patients. Although the effect of pain improvement has been mainly focused on SNRIs, result from this study suggests the need for further research and validation on the effect of NaSSA for pain control.
Depression ; Humans ; Inpatients ; Nociceptive Pain ; Norepinephrine ; Serotonin ; Serotonin Uptake Inhibitors

No abstract available.
Animals ; Clomipramine* ; Preoptic Area* ; Rats* ; Serotonin Uptake Inhibitors* ; Serotonin*

A large body of research including animal and human studies has confirmed the crucial role of the serotonin (5-HT) system in the regulation of nociception and chronic pain-related behaviors. In recent years, the functional status of the 5-HT system in descending inhibition and facilitation of spinal nociceptive processing has been reevaluated by novel genetic manipulation techniques and selective agents for 5-HT receptor subtypes. Although these studies shed more light on several aspects of descending 5-HT and spinal 5-HT receptors functioning in descending modulation in pain perception, the current knowledge about the specific role of descending 5-HT system in the induction and maintenance of persistent pain remains fragmentary. In this paper, we review the available data from recent studies of the inhibitory or facilitatory influence from descending 5-HT-spinal 5-HT receptor system in acute and persistent pain, attempt to dissect the involvement of this signaling pathway in neural circuits of maintenance of persistent pain and discuss some issues that need to be considered for further pain research.
Animals ; Humans ; Pain ; physiopathology ; Receptors, Serotonin ; physiology ; Serotonin ; physiology