Alpha 1-adrenoceptor mediation of urinary bicarbonate excretion.

TitleAlpha 1-adrenoceptor mediation of urinary bicarbonate excretion.
Publication TypeJournal Article
Year of Publication1988
JournalThe American journal of physiology
Issue6 Pt 2

The adrenoceptor mechanism that mediates the reduction of urinary sodium (UNa V) and bicarbonate (UHCO3 V) excretion during 1.0-Hz renal nerve stimulation (RNS) was evaluated in 21 anesthetized dogs. In each animal RNS decreased UNa V and UHCO3 V without changing mean arterial pressure, renal blood flow, or glomerular filtration rate. After these initial responses, dogs were administered phentolamine [2.0 intrarenal artery (ira); n = 7], prazosin (0.7 ira; n = 5), (+/- )-propranolol (2.0 ira; n = 4), or atenolol (50 mg/kg iv; n = 5) and the renal responses to RNS were again tested. Both the antinatriuretic response and reduction of UHCO3 V during RNS were abolished by alpha 1/alpha 2-adrenoceptor blockade with phentolamine and by alpha 1-adrenoceptor antagonism with prazosin. beta-Adrenoceptor blockade with (+/- )-propranolol (beta 1/beta 2) or atenolol (beta 1) did not alter either the decrease in UNa V or UHCO3 V after RNS. These results provide further evidence that, during low-frequency RNS, reduction of UNa V is mediated in part by carbonic anhydrase-dependent bicarbonate reabsorption. These antinatriuretic responses and decreases in UHCO3 V during 1.0-Hz RNS are mediated by adrenergic neurotransmitter stimulation of alpha 1-adrenoceptors.

Short TitleAm J Physiol
Enter your linkblue username.
Enter your linkblue password.
Secure Login

This login is SSL protected