[3H]Serotonin is accumulated by a specific set of amacrine cells in the rabbit retina. These cells also accumulate the neurotoxin, 5,7-dihydroxytryptamine, and show signs of necrosis within 4 h of in vivo exposure to the drug. Biochemical analysis of [3H]serotonin uptake reveal a sodium- and temperature-dependent, high affinity uptake system with a Km of 0.94 microM and Vmax of 1.08 pmol/mg pro...

The administration of methyldopa (200 mg/kg i.p.) induced a green fluorescence typical of catecholamine fluorescence, in regions of the brain stem which coincided with all the major serotonin cell groups, including the B1, B2, and B3 cell groups in the medulla. Prior administration of 5,7-dihydroxytryptamine (5,7-DHT), a neurotoxin relatively specific for serotonin neurons, prevented the appear...

A better understanding of the molecular mechanisms of signaling by the neurotransmitter serotonin is required to assess the hypothesis that defects in serotonin signaling underlie depression in humans. Caenorhabditis elegans uses serotonin as a neurotransmitter to regulate locomotion, providing a genetic system to analyze serotonin signaling. From large-scale genetic screens we identified 36 mu...

Serotonin is an important brain chemical that acts as a neurotransmitter to communicate information among nerve cells. Serotonin’s actions have been linked to alcohol’s effects on the brain and to alcohol abuse. Alcoholics and experimental animals that consume large quantities of alcohol show evidence of differences in brain serotonin levels compared with nonalcoholics. Both shortand long-term ...

During development of the Drosophila nerve cord, neuroblast 7-3 gives rise to a pair of mitotic sister serotonin neurons in each hemisegment. Here we show that the zinc finger gene eagle, which is expressed in neuroblast 7-3, is essential for specifying the fate of serotonin neurons. We find that loss-of-function eagle mutations produce an unusual differential phenotype with respect to the sist...

Serotonin is a naturally occurring “messenger” protein that is found primarily in the gastrointestinal system, certain blood cells (platelets) and the central nervous system (brain and brain stem). Abnormal activity of this messenger protein has been implicated in both migraine and depression, and medications that modify serotonin can be effective in treating both disorders. Such medications in...

To elucidate the regulation of serotonin transporter (SERT) function via its membrane trafficking, we investigated involvement ubiquitin E3 ligase HRD1 (HMG-CoA reductase degradation protein), which participates in endoplasmic reticulum (ER)-associated (ERAD), functional SERT. Cells transiently expressing wild-type SERT or a C-terminal deletion mutant (SERTΔCT), protein predicted to be misfolde...

Voluntary wheel running has long been known to induce precursor cell proliferation in adult hippocampal neurogenesis in rodents. However, mechanisms that couple activity with the promitotic effect are not yet fully understood. Using tryptophan hydroxylase (TPH) 2 deficient (Tph2-deficient) mice that lack brain serotonin, we explored the relationship between serotonin signaling and exercise-indu...