The mechanism of action of angiotensin II in the rat snake, Ptyas korros.
The hindquarter of the rat snake, Ptyas korros, was isolated for perfusion study in order to investigate the mechanism of action of angiotensin (ANG) II. Both ANG II and norepinephrine (NE) produced concentration-dependent increases in perfusion pressure. [Sar1, Ile8] ANG II significantly attenuated the response to ANG II but not that of NE. Phentolamine significantly reduced the responses to both ANG II and NE, with much greater inhibition on NE than ANG II. These findings suggest the presence of ANG II receptors and alpha-adrenergic receptors in the hindquarter. Since tyramine did not exert any increase in perfusion pressure, the release of ANG II-stimulated catecholamines was probably not involved in the increase in perfusion pressure to ANG II in the present preparation. The partial attenuation of the response to ANG II by phentolamine, therefore, suggests that ANG II may act directly on both specific ANG II receptors and alpha-adrenergic receptors.
D015059:1-Sarcosine-8-Isoleucine Angiotensin II / Q000494:pharmacology; D000804:Angiotensin II / Q000037:antagonists & inhibitors / Q000502:physiology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D008297:Male; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000502:physiology; D010477:Perfusion; D010646:Phentolamine / Q000494:pharmacology; D012911:Snakes / Q000502:physiology*; D014439:Tyramine / Q000494:pharmacology
D000804:Angiotensin II; D015059:1-Sarcosine-8-Isoleucine Angiotensin II; D009638:Norepinephrine; D014439:Tyramine; D010646:Phentolamine