Plasma immunoreactive atrial natriuretic factor (IR-ANF) increases markedly after alpha 2-adrenergic stimulation with clonidine in normally-hydrated rats.
Clonidine, an alpha 2-adrenergic agonist, induced a marked, dose-related increase of plasma IR-ANF in normally-hydrated rats. Maximal ANF release was observed at 10 min after injection of 50 micrograms clonidine, rising from 40.5 +/- 4.6 pg/ml (X +/- SEM) to 1064.4 +/- 22.4 pg/ml. This effect on plasma IR-ANF was partially blocked by pretreatment with 0.8 mg naloxone, whereas synthetic Arg8-vasopressin (AVP) did not inhibit clonidine's action. These findings indicate that increased ANF release may be involved in the mechanism of clonidine-induced diuresis. The clonidine's effect on ANF release may be mediated via activation of opioid receptors besides stimulation of alpha 2-adrenergic receptors.
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D009320:Atrial Natriuretic Factor / Q000097:blood*; D003000:Clonidine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007700:Kinetics; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D014556:Urine; D014882:Water-Electrolyte Balance
D011942:Receptors, Adrenergic, alpha; D001127:Arginine Vasopressin; D009270:Naloxone; D009320:Atrial Natriuretic Factor; D003000:Clonidine