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Patients with bulimia nervosa (BN) have disturbances of mood and behavior related to monoamine activities. There have been no reports concerning salivary concentrations of 5-hydroxytryptamine (5-HT) in patients with eating disorders such as anorexia nervosa (AN) and BN. In order to elucidate the involvement of 5-HT in eating disorders, 5-HT levels in the saliva of patients with BN were measured. Salivary 5-HT levels in patients with avoidant personality disorder (APD) were also measured as an active control. 5-HT levels in the saliva of patients with BN and APD were compared with those of 32 healthy volunteers. Simultaneously, salivary 3,4-dihydroxyphenylacetic acid (DOPAC) was measured using HPLC-ECD. 5-HT levels were 41.04 ± 14.41 in 11 patients with BN (10 women and 1 man, average age 19.6 years), 78.55 ± 45.55 in 5 patients with APD (3 women and 2 men, average age 19.2 years) and 8.91 ± 1.10 ng/ml in 32 healthy controls (25 women and 7 men, average age 21.7 years), respectively. This is the first report that salivary concentrations of 5-HT were significantly higher in BN (p < 0.05) and in APD than those in healthy controls. We found no significant differences among the salivary DOPAC levels in BN, APD and those of healthy controls. There were no significant differences in body mass index among the three groups. 5-HT concentrations in the saliva may be a useful marker of stress or eating disorders. [ABSTRACT FROM AUTHOR]

The ferret (Mustela putorius furo), a carnivore weighting 1–1.5 kg, is highly valued as a small animal model for determining the emetic activity of cytotoxic drugs. Because of its sensitivity to emetic stimuli, the ferret is now being used routinely for testing novel cytotoxic drugs and antiemetic agents. In our laboratory, ferrets were evaluated on their behavioral changes, pathological changes and pharmacological responses to cytotoxic drug-induced emesis. Cisplatin-induced emesis in ferrets was inhibited by 5-HT3 receptor antagonists in a dose dependent manner. 5-HT levels in the area postrema and in the ileum were increased by cytotoxic agents. Both abdominal vagotomy and ondansetron, a 5-HT3 receptor antagonist, remarkably inhibited cisplatin-induced emesis and cisplatin-induced increase in 5-HT levels in the area postrema. The cisplatin-induced increase of the ileal 5-HT levels, however, was not inhibited by vagotomy or ondansetron. Furthermore, compared with intraperitoneal administration, oral administration of ondansetron blocked cyclophosphamide-induced emesis more effectively and significantly. These results suggest that cytotoxic drugs induce emesis mainly through actions on the gastrointestinal tract. Cytotoxic drugs may cause 5-HT release from the enterochromaffin (EC) cells of the intestinal mucosa to stimulate 5-HT3 receptors on the afferent vagal fibers. Stimulation from the afferent vagal nerves appear to produce an increase in 5-HT levels in the area postrema. The increased 5-HT levels in the area postrema might trigger the emetic response induced by cytotoxic agents. In this review, we also discuss abdominal afferent vagus nerve activity and 5-HT release from EC cells using data from our laboratory. [ABSTRACT FROM AUTHOR]

Discusses the intracellular regulatory mechanisms of 5-hydroxytryptamine (5-HT) release from enterochromaffin cells, in response to receptor stimulation. Role of autoreceptors on 5-HT release; Cholinergic mechanisms that stimulates 5-HT release; Influence of intracellular calcium ion on 5-HT release.

Determines the levels of acetylcholine (ACh), choline and dopamine (DA) in rat brain tissues after isatin administration to elucidate the role of isatin in regulating ACh levels. Description of isatin; ACh and DA concentrations in various brain regions before isatin administration to Wistar Kyoto rats; Effects of isatin microdialysis on ACh release from rat striatum.