Altered renal alpha-adrenoceptor regulation in DOCA-salt rats: chronic effects of alpha 1- and alpha 2-receptor blockers.
Effects on the alpha-adrenoceptor binding in the kidneys of DOCA-salt rats were examined after a 6 week treatment of once-daily injections of prazosin, a selective alpha 1-adrenoceptor blocker; yohimbine, a selective antagonist for alpha 2-adrenoceptors; and prazosin plus yohimbine. alpha 1-Receptor binding was decreased by prazosin, while alpha 2-receptor binding was increased by simultaneous administration of prazosin + yohimbine. Equilibrium dissociation constants (KD) for [3H]prazosin and [3H]yohimbine were not significantly different (between groups). Since these drugs can prevent the development of hypertension in DOCA-salt rats, the present data strongly suggests that selective alteration of alpha-receptor-mediated physiological responses is unrelated to decreased or increased binding site densities. The mechanism of hypertension prevention may involve changes in the coupling of receptors to postreceptor events.
Saiz
J
J
Torres
A
A
Martinez-Sierra
R
R
Sanchez
A
A
D000317:Adrenergic alpha-Antagonists / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D003900:Desoxycorticosterone; D006973:Hypertension / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D011224:Prazosin / Q000378:metabolism / Q000494:pharmacology; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D012965:Sodium Chloride; D015016:Yohimbine / Q000378:metabolism / Q000494:pharmacology
D000317:Adrenergic alpha-Antagonists; D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D003900:Desoxycorticosterone; D012965:Sodium Chloride; D011224:Prazosin