Whole body exposure to high doses of ionizing radiation is associated with small intestinal and colonic dysfunction, the etiology of which remains unknown. In this study, we investigated the role of both neural and nonneural 5-hydroxytryptamine (5-HT)-mediated pathways in radiation-induced attenuation and recovery of colonic secretory function. Rats were exposed to whole body 10-Gy gamma irradi...

Selective serotonin reuptake inhibitors (SSRI) are aimed at increasing brain 5-HT tone; however, this expected effect has a slow onset after starting SSRI treatment because of initial activation of 5-HT(1A) autoreceptor-mediated negative feedback of 5-HT release. After chronic SSRI treatment, 5-HT(1A) autoreceptors desensitize, which allows 5-HT tone elevation. Because 5-HT(1A) receptor (5-HT(1...

The distribution and function of the 5-hydroxytryptamine (5-HT(2A)) receptor were investigated in the intestines of wild-type (5-HT(2A) +/+) and knockout (5-HT(2A) -/-) mice. In 5-HT(2A) +/+ mice, rats, and guinea pigs, 5-HT(2A) receptor immunoreactivity was found on circular and longitudinal smooth muscle cells, neurons, enterocytes, and Paneth cells. Muscular 5-HT(2A) receptors were concentra...

We investigated the effects of partial bladder outlet obstruction (BOO) on the function and gene expression of 5-hydroxytryptamine (5-HT) receptor subtypes in rat bladder. Isometric contractions of the isolated bladders from sham-operated control and BOO rats were examined. The contractile responses to 5-HT were significantly increased in BOO rat bladder strips, while the responses to KCl, carb...

The 5-HT(5A) receptor is the least understood serotonin (5-HT) receptor. Here, we electrophysiologically identify and characterize a native 5-HT(5A) receptor current in acute ex vivo brain slices of adult rodent prefrontal cortex. In the presence of antagonists for the previously characterized 5-HT(1A) and 5-HT₂ receptors, a proportion of layer V pyramidal neurons continue to show 5-HT-elicited...

5-Hydroxytryptamine (serotonin) (5-HT) type 3 (5-HT(3)) receptors are members of an anesthetic-sensitive superfamily of Cys-loop ligand-gated ion channels that can be formed as homomeric 5-HT(3A) or heteromeric 5-HT(3AB) receptors. When the efficacious agonist 5-HT is used, the inhaled anesthetics halothane and chloroform (at clinically relevant concentrations) significantly reduce the agonist ...

The serotonin 5-HT(4) receptor (5-HT(4)R) is coded by a complex gene that produces four mRNA splice variants in mice (5-HT(4(a))R, 5-HT(4(b))R, 5-HT(4(e))R, 5-HT(4(f))R). This receptor has highly dynamic expression in brain development and its splice variants differ in their developmental trajectories. Since 5-HT(4)Rs are important in forebrain function (including forebrain control of serotoner...

The purpose of this study was to evaluate the influence of exercise on plasma tryptophan (TRP) and free serotonin (f5-HT), whole blood-5-HT (WB-5-HT) and f5-HT/WB-5-HT ratio in Italian Saddle horses. Six clinically healthy Italian Saddle horses were subjected to a 450 meters obstacles course. Blood samples were collected from each horse by jugular venipuncture using vacutainer tubes with K(3)-E...

The "club drug" 3,4-methylenedioxymethamphetamine (MDMA; also known as ecstasy) binds preferentially to and reverses the activity of the serotonin transporter, causing release of serotonin [5-hydroxytryptamine (5-HT)] stores from nerve terminals. Subsequent activation of postsynaptic 5-HT receptors by released 5-HT has been shown to be critical for the unique psychostimulatory effects of MDMA. ...

The plasma membrane 5-HT transporter (SERT) is the major protagonist in regulating extracellular 5-HT concentration and constitutes the target of drugs used to treat a host of metabolic and psychiatric disorders. The exact mechanisms sustaining SERT function still remain elusive. The present work exploits the properties of the 1C11 neuroectodermal progenitor, which acquires, upon 4 days of diff...