Further characterization of forebrain serotonin receptors mediating tachycardia in conscious rats.
It has been shown recently that activation of forebrain serotonin1A (5-HT1A) receptors, likely within the preoptic area, elicits a slight increase in blood pressure and a substantial tachycardia. The present studies were designed to characterize: (1) the requirement of the 5-HT1A receptor agonist R(+)-8-hydroxy-2-(di-n-propylamino) tetralin [R(+)8-OH-DPAT]-induced tachycardia on the integrity of serotonergic innervation of the preoptic area, (2) the ability of the 5-HT1A receptor partial agonist buspirone to elicit cardiovascular responses when microinjected into the preoptic area, (3) the role of 5-HT2 and 5-HT3 receptors in the preoptic area in cardiovascular regulation, and (4) the site specificity of the tachycardia produced by R(+)8-OH-DPAT. The data suggest that activation of 5-HT1A receptors, but not 5-HT2 or 5-HT3 receptors, within or very near the preoptic area increases blood pressure and heart rate in conscious rats. Furthermore, the full response is dependent on afferent serotonergic innervation, suggesting a presynaptic modulatory role for 5-HT in the preoptic area.
Szabó
A
A
Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City 66160-7417, USA.
Butz
B L
BL
Alper
R H
RH
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002065:Buspirone / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D011301:Preoptic Area / Q000187:drug effects / Q000502:physiology / Q000503:physiopathology*; D016548:Prosencephalon / Q000187:drug effects / Q000502:physiology / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology*; D044263:Receptors, Serotonin, 5-HT1; D044406:Receptors, Serotonin, 5-HT3; D012701:Serotonin / Q000378:metabolism* / Q000494:pharmacology; D013569:Synapses / Q000502:physiology; D013610:Tachycardia / Q000503:physiopathology*
D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D044406:Receptors, Serotonin, 5-HT3; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D002065:Buspirone; D004298:Dopamine; D009638:Norepinephrine