Effects of chemical sympathectomy with 6-hydroxydopamine on alpha- and beta-adrenoceptors and muscarinic cholinoceptors in rat kidney.
The autonomic receptors in the rat kidney were characterized using the radioligands [3H]prazosin, [3H]clonidine, [3H]dihydroalprenolol (DHA) and [3H]quinuclidinyl benzilate (QNB). The specific binding of [3H]prazosin, [3H]clonidine, [3H]DHA and [3H]QNB to rat kidney membranes was saturable and of high affinity, and showed a pharmacological specificity as well as stereospecificity which characterized renal alpha 1-, alpha 2- and beta-adrenoceptors and muscarinic cholinoceptors, respectively. There was a relatively greater density of alpha-adrenoceptors than beta-adrenoceptors or muscarinic cholinoceptors in the rat kidney. Chemical sympathectomy of rats with 6-hydroxydopamine X HBr (6-OHDA, 50 X 2 mg/kg i.v., 24 h interval) caused a significant increase (21-56%) in the Bmax values for renal [3H]prazosin, [3H]clonidine and [3H]DHA binding at 1 and 2 weeks following the treatment, without a change in the Kd values. 6-OHDA treatment had no significant effect on the Kd and Bmax values for [3H]QNB binding at 1-3 weeks after the treatment. The norepinephrine (NE) concentration was reduced (68-76%) in the 6-OHDA-treated rat kidney. In conclusion, the present study provides biochemical evidence for the possible localization of postsynaptic alpha 1-, alpha 2- and beta-adrenoceptors and muscarinic cholinoceptors in the rat kidney and also for the regulation of these adrenoceptors by the sympathetic nervous system.
D000818:Animals; D003000:Clonidine / Q000494:pharmacology; D004082:Dihydroalprenolol / Q000494:pharmacology; D006892:Hydroxydopamines; D066298:In Vitro Techniques; D007668:Kidney / Q000294:innervation*; D007700:Kinetics; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D016627:Oxidopamine; D011224:Prazosin / Q000494:pharmacology; D011813:Quinuclidinyl Benzilate / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D011976:Receptors, Muscarinic / Q000187:drug effects*; D013563:Sympathectomy, Chemical
D006892:Hydroxydopamines; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D011976:Receptors, Muscarinic; D004082:Dihydroalprenolol; D011813:Quinuclidinyl Benzilate; D016627:Oxidopamine; D003000:Clonidine; D009638:Norepinephrine; D011224:Prazosin