Vasopressin may be a neurotransmitter and in vivo experiments suggest that it acts on monoamine metabolism. The rat hippocampal slice contains serotonergic nerve terminals but not cell bodies; we studied the effect of vasopressin on the synthesis and release of serotonin from these nerve terminals during depolarization. Incubation of slices in a buffer containing 60 mM K+ (high K buffer) for 10...

Serotonin is synthesized by two distinct tryptophan hydroxylases, one in the brain and one in the periphery. The latter is known to be unable to cross the blood-brain barrier. These two serotonin systems have apparently independent functions, although the functions of peripheral serotonin have yet to be fully elucidated. In this study, we have investigated the physiological effect of peripheral...

BACKGROUND AND PURPOSE Serotonin released from platelets has been suggested as one substance causing the vasospasm following subarachnoid hemorrhage. We studied whether such serotonin is able to constrict pial vessels. METHODS We studied the uptake of serotonin in pial perivascular nerves by immunohistochemistry. We measured the contractile response in rat basilar artery after in vitro incuba...

Paracrine signaling between cholangiocytes and stromal cells regulates biliary remodeling. Cholangiocytes have neuroepithelial characteristics and serotonin receptor agonists inhibit their growth, but whether they are capable of serotonin biosynthesis is unknown. We hypothesized that cholangiocytes synthesize serotonin and that cross talk between liver myofibroblasts (MF) and cholangiocytes reg...

State-dependent reductions in serotonin delivery to upper airway dilator motoneuron activity may contribute to sleep apnea. The functional significance of serotonin receptor subtypes implicated in excitation of dilator motor neurons was evaluated in anesthetized, paralyzed, mechanically ventilated adult rats (n = 108). The effects of antagonists selective for serotonin receptor subtypes 2A, 2C,...

Serotonin has a multifunctional role in many different organs serving either as a neurotransmitter in the central nervous system or a paracrine factor in the gastrointestinal tract. Over 90% of serotonin is synthesised in the enterochromaffin cells of the intestine and subsequently taken up by platelets. The involvement of platelet-derived serotonin in liver mass restoration after partial hepat...

(+/-)-3,4-Methylenedioxyamphetamine (MDA), an amphetamine analog with hallucinogenic activity, produced selective long-lasting reductions in the level of serotonin, the number of serotonin uptake sites, and the concentration of 5-hydroxyindoleacetic acid in rat brain. Morphological studies suggested that these neurochemical deficits were due to serotonin nerve terminal degeneration. These resul...

CONTEXT MDMA (3,4-methylenedioxymethamphetamine, also popularly known as "ecstasy") is a popular recreational drug that produces loss of serotonin axons in animal models. Whether MDMA produces chronic reductions in serotonin signaling in humans remains controversial. OBJECTIVE To determine whether MDMA use is associated with chronic reductions in serotonin signaling in the cerebral cortex of ...

BACKGROUND In 2006, a US Food and Drug Administration (FDA) alert warned about the potential life-threatening risk of serotonin syndrome when triptans are used in combination with selective serotonin reuptake inhibitors (SSRIs) or selective serotonin/norepinephrine reuptake inhibitors (SNRIs). This American Headache Society Position Paper further reviews the available evidence of the potential ...