Regional differences in serotonergic contractile sensitivity mediated by 5-HT2 receptors in rat aorta.
The present studies examined serotonergic contractile sensitivity mediated by 5-HT2 receptors in thoracic and abdominal regions of rat aorta. Increasing concentrations of 5-HT (10 nM-100 microM) in the presence or absence of the selective 5-HT2 antagonist ketanserin (5 nM) produced differential concentration-response curves in thoracic and abdominal aortic ring preparations. Abdominal aortic preparations were significantly more sensitive to 5-HT than thoracic regions. Regional variations in maximal response produced by 5-HT were not observed. Ketanserin produced distinct rightward shifts in the 5-HT concentration-response curves, revealing a similar profile of sensitivity in thoracic and abdominal aorta. These data suggest that regional patterns in 5-HT-induced contractile responses in rat aorta are mediated by 5-HT2 sites exhibiting differential, site specific sensitivity.
Sufka
K J
KJ
Neuropharmacology Laboratory College of Pharmacy and Health Sciences, Drake University, Des Moines, IA 50311.
Stratton
D B
DB
Giordano
J
J
D000818:Animals; D001012:Aorta, Abdominal / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D001013:Aorta, Thoracic / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D066298:In Vitro Techniques; D007650:Ketanserin / Q000494:pharmacology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*
D011985:Receptors, Serotonin; D012701:Serotonin; D007650:Ketanserin