Inhibition by D 600 of norepinephrine- and clonidine-induced responses of the aortae from normotensive (WKY) and spontaneously hypertensive rats (SHR).
Comparison was made of the inhibition by D 600 of the norepinephrine (NE)- and clonidine-induced responses of aortic strips from normotensive (WKY) and spontaneously hypertensive rats (SHR). Clonidine-induced responses of aortae from both strains of rats were markedly more susceptible to inhibition by D 600 than those of NE. Omission of calcium from the physiological solution resulted in a greater reduction in response to clonidine. Aortae from SHR were less susceptible to inhibition by D 600 but showed no difference from WKY rats in their responses in nominally calcium-free physiological solutions. Our results clearly indicate a greater dependence on extracellular calcium by clonidine-induced responses of the aortae relative to those of NE.
D000818:Animals; D001011:Aorta / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D003000:Clonidine / Q000037:antagonists & inhibitors*; D005711:Gallopamil / Q000494:pharmacology*; D006973:Hypertension / Q000378:metabolism*; D066298:In Vitro Techniques; D009638:Norepinephrine / Q000037:antagonists & inhibitors*; D051381:Rats; D011919:Rats, Inbred Strains; D014661:Vasoconstriction / Q000187:drug effects*; D014700:Verapamil / Q000031:analogs & derivatives*
D002121:Calcium Channel Blockers; D005711:Gallopamil; D014700:Verapamil; D003000:Clonidine; D009638:Norepinephrine