The characteristics of alpha-adrenoceptors mediating the renal nerve induced antinatriuresis and antidiuresis in hypertensive rats.
Selective alpha-adrenoceptor and calcium antagonists have been used to determine both the alpha 1-adrenoceptor subtype and the extracellular calcium requirement for renal nerve-mediated antinatriuresis and antidiuresis in deoxycorticosterone acetate (DOCA)-salt and two-kidney, one clip (2K1C) Goldblatt hypertensive rats. Stimulation of the renal nerves at low frequencies reduced urine flow and absolute and fractional sodium excretions by 40-60% in pentobarbitone anaesthetized control, sham-operated, DOCA-salt and 2K1C Goldblatt hypertensive rats. Administration of prazosin, but not idazoxan, inhibited the renal nerve-induced excretory responses in both models of hypertension, a result compatible with the involvement of alpha 1-adrenoceptors. By contrast, the calcium antagonist inhibited the renal nerve-dependent antinatriuresis and antidiuresis in DOCA-salt but not 2K1C Goldblatt hypertensive rats. These results showed that the renal nerves mediated their action via alpha 1-adrenoceptors, but that the postreceptor responses were dependent on extracellular calcium in DOCA-salt but not 2K1C Goldblatt rats.
Akpogomeh
B A
BA
Department of Physiology, The Medical School, Birmingham, UK.
Johns
E J
EJ
D000818:Animals; D002118:Calcium / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D003900:Desoxycorticosterone / Q000009:adverse effects; D004231:Diuresis / Q000502:physiology*; D006973:Hypertension / Q000503:physiopathology*; D006978:Hypertension, Renovascular / Q000503:physiopathology; D007668:Kidney / Q000294:innervation*; D008297:Male; D009318:Natriuresis / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000145:classification*; D012982:Sodium, Dietary / Q000009:adverse effects
D002121:Calcium Channel Blockers; D011942:Receptors, Adrenergic, alpha; D012982:Sodium, Dietary; D003900:Desoxycorticosterone; D002118:Calcium