[Mechanism of vascular desensitization to agonists].
The patterns and mechanism of vascular desensitization to agonists were studied in isolated arteries of Wistar and SHR rats. The results showed that: (1) Arteries were much easier to desensitize peptidergic agonists (A II, AVP) than catecholaminer gic agonists (NE, PE); (2) the desensitization induced by peptidergic agonists and catecholaminer gic agonists were homologous within 30 minutes; (3) the endothelium-EDRF-cGMP pathway was not involved in agonist-induced desensitization; (4) inhibition of surface receptor internalization by phenylarsine oxide (PAO, 10(-5)mol/L) could transiently reverse the desensitization and the blocking of intracellular receptor re-insertion into the membrane by chloroauine (10(-5)mol/L) could accelerate the desensitization in varying degrees with different arteries, which demonstrated the involvement of receptor cycling in homologous desensitization, but was not the unique mechanism; (5) there was no change in the function of voltage-dependent Ca2+ channel during homologous desensitization; (6) the concentration-contraction curve of GTP gamma S shifted down-ward during homologous desensitization, suggesting the functional change of G protein (s); (7) the desensitization to agonists didn't decrease in arteries of SHR compared with the arteries of Wistar rats.
Cao
J
J
Institute of Basic Medical Sciences, CAMS, Beijing.
Chen
M
M
Wang
Q
Q
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001152:Arsenicals / Q000494:pharmacology*; D002738:Chloroquine / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D013618:Tachyphylaxis
D001152:Arsenicals; C029341:oxophenylarsine; D000804:Angiotensin II; D002738:Chloroquine; D009638:Norepinephrine