Hydrozoan larvae normally metamorphose in response to an obligate external environmental cue. Application of certain artificial chemical stimuli will also induce metamorphosis. These chemicals and their inhibitors have been used to define and order some of the signal transduction events involved in this process. Results from this study show that exogenous application of serotonin (5-HT) will in...

Dysregulation of the 5-HT(2A) receptor is implicated in both the etiology and treatment of schizophrenia. Although the essential role of 5-HT(2A) receptors in atypical antipsychotic drug actions is widely accepted, the contribution of 5-HT(2A) down-regulation to their efficacy is not known. We hypothesized that down-regulation of cortical 5-HT(2A) receptors contributes to the therapeutic action...

The influence of endothelial cells on the response of smooth muscle in the rabbit coronary artery to 5-hydroxytryptamine (5-HT) was investigated with intracellular microelectrode and mechanical methods. Recent work has suggested that 5-HT stimulates the release of a smooth muscle relaxing factor from endothelial cells, which will reduce the direct constrictor action of 5-HT on the artery wall. ...

The inhibitory effects of the endothelium against ergonovine-induced contraction were examined in isolated porcine coronary arteries under normal conditions and after endothelial regeneration. Endothelium-dependent responses were examined in vitro in normal Yorkshire pigs (n = 16) and in pigs that had undergone balloon endothelium removal of the left anterior descending coronary artery (LAD) 4 ...

The serotonin (5-HT)(2A/2c) agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), the 5-HT2C agonist 6-chloro-2-[1-piperazinyl]-pyrazine and the 5-HT2A partial agonist m-chloro-phenylpiperazine (mCPP) were injected bilaterally into the medial prefrontal cortex of male rats. DOI and mCPP, but not 6-chloro-2-[1-piperazinly]-pyrazine, elicited a dose-dependent head-twitch response (HTR). DO...

The distribution of serotonin (5-HT)-like immunoreactive (5-HT-LI) nerves and the potential role of 5-HT as a vasoconstrictor transmitter in large cerebral arteries of the rabbit were examined. 5-HT-LI fibers with weak immunofluorescence were observed in the anterior cerebral, middle cerebral, and basilar arteries when fixed by immersion after dissection from exsanguinated animals. The 5-HT-LI ...

Post-burn trauma significantly raises tissue serotonin concentration at the initial stages of injury, which leads us to investigate its possible role in post burn wound healing. Therefore, we planned this study to examine the role of serotonin in wound healing through in vitro and in vivo models of burn injuries. Results from in vitro analysis revealed that serotonin decreased apoptosis and inc...

This study was carried out aiming to reach behavioral and neuropharmacological evidence of the permeability of the blood-brain barrier (BBB) to serotonin systemically administered in quails. Serotonin injected by a parenteral route (250-1000 microg x kg(-1), sc) elicited a sequence of behavioral events concerned with a sleeping-like state. Sleeping-like behaviors began with feather bristling, r...

BACKGROUND Both hypertension and high blood pressure variability (BPV) are involved in cardiovascular damage. This comparative study was designed to explore the possible effects of both of these phenomena on the cardiovascular system. METHODS The high BPV model of 16-week sinoaortic denervated (SAD) rats and the hypertension model of spontaneously hypertensive rats (SHR) were used for compari...

The present study was conducted to investigate the antinociceptive action of relationship between Herba Epimedium (HE) and 5-HT1A receptor, between Herba Epimedium (HE) and 5-HT2A receptor. We used the hot-plate method and the writhing assay in mice by the intracerebroventricular (i.c.v.) injection and observed the analgesic effect of HE. Furthermore, through the i.c.v. injection, 5-HT1A recept...