Naloxone and TRH affect regional blood flows in the anesthetized rabbit.
The cardiovascular effects of IV naloxone and a subsequent administration of TRH IV were studied in the rabbit. Naloxone caused a vasodilation in the myocardium and adrenal glands. Naloxone elicited an increment in cerebral blood flow in several regions which attenuated the cerebrovasodilating effect of TRH in a few regions. The blockade of endogenous opioids with naloxone did not modify the peripheral vasoconstricting effect of TRH or affect the vascular effects of TRH mediated by the peripheral sympathetic nerves. The results indicate that naloxone has a vasodilating effect in the myocardium and CNS in anesthetized rabbits. The major part of the cardiovascular effect of TRH is not dependent on mechanisms sensitive to naloxone.
Koskinen
L O
LO
Department of Physiology and Medical Biophysics, University of Uppsala, Sweden.
D000311:Adrenal Glands / Q000098:blood supply; D000758:Anesthesia; D000818:Animals; D002560:Cerebrovascular Circulation / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects; D004723:Endorphins / Q000502:physiology; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects
D004723:Endorphins; D009270:Naloxone; D013973:Thyrotropin-Releasing Hormone