Pharmacological evidence that circumventricular organs may participate in the pressor effect of central serotonin.
The present study was to investigate the role of '5-HT2-like' receptors in the circumventricular organs in the pressor response elicited by the central injection of serotonin (5-HT) to conscious rats. The increase in blood pressure induced by intracerebroventricular (i.c.v.) 5-HT (2.5 micrograms) was attenuated by intravenous pretreatment will, the peripheral 5-HT2 antagonist xylamidine (100 or 300 micrograms/kg). A combination of xylamidine with prazosin or a V1-vasopressin antagonist did not produce a further attenuation in the pressor response. Our data suggest that when administered i.c.v., 5-HT increases blood pressure by acting on 5-HT2-like receptors located in circumventricular organs as well as areas of the brain protected by the blood-brain barrier.
Pérgola
P E
PE
Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City 66103.
Alper
R H
RH
D000578:Amidines / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001921:Brain / Q000502:physiology*; D005070:Evans Blue; D006339:Heart Rate / Q000187:drug effects; D007276:Injections, Intraventricular; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000008:administration & dosage / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology
D000578:Amidines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin; D005070:Evans Blue; C005894:xylamidine