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*

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

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

Humans ; Serotonin ; Cardiovascular Diseases

Growing evidence indicates that the serotonin system is important in learning and memory. In particular, several preclinical and clinical studies suggest that modulating the 5-HT1A receptor can influence learning and memory, and indeed, it has been observed that presynaptic 5-HT1A receptor agonists and postsynaptic 5-HT1A receptor antagonists tend to ameliorate the learning/memory impairment induced by various methods. In contrast, post-synaptic 5-HT1A receptor agonists tend to decrease the learning/memory function. These observations suggest the possibility that modulating neurotransmission mediated by the 5-HT1A receptor may be effective as a therapeutic strategy for enhancing learning and memory in various neuropsychiatric disorders. Unfortunately, there is no available discussion on the relationship between 5-HT1A receptor and learning/memory in Korea. This article reviews the clinical or preclinical literature on this issue.
Korea ; Learning* ; Memory* ; Receptor, Serotonin, 5-HT1A* ; Serotonin ; Synaptic Transmission

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

Serotonin is one of the most important neurotransmitters involved in the pathophysiology of depressive illness. The assessment of alteration of cerebral serotonin has been still controversial but interesting topic to study. Recently, increasing evidence has accumulated that the N100 amplitude slope reflects cerebral serotonin activity and treatment response of selective serotonin reuptake inhibitors (SSRIs). We report on two patients who showed abrupt mood changes and side effects after taking SSRI antidepressants. In both patients, aberrantly high N100 amplitude slopes were observed. Our cases suggest that the N100 amplitude slope may be a reliable indicator for predicting manic conversion and side effects in the SSRI treatment of depressive patients. Controlled studies are necessary to confirm whether a high N100 amplitude slope is a useful indicator of SSRI supersensitivity.
Antidepressive Agents ; Depression ; Humans ; Neurotransmitter Agents ; Serotonin ; Serotonin Uptake Inhibitors