Increased duodenal HCO3- output after blood volume expansion in the rat: an effect mediated by atrial natriuretic peptide (ANP)?
Duodenal HCO3- secretion was measured by in-situ titration in chloralose-anaesthetized rats. The effects of hypervolaemia, induced by i.v. injections of an albumin infusion, on duodenal HCO3- secretion were investigated. A 10% increase in blood volume increased duodenal HCO3- secretion by about 50%, and this effect was unaffected by splanchnicotomy. If the splanchnicotomy was combined with cervical vagotomy, the basal HCO3- secretion was lower but the increase in secretion after 10% blood volume expansion with albumin was still 50%. If the same increase in blood volume was produced in splanchnicotomized and vagotomized rats in which the right atrial appendix had been removed, a procedure that markedly reduces the ANP (atrial natriuretic peptide)-producing cells, no increase in secretion could be observed. Intravenous injections of alpha-r-ANP (10 micrograms kg-1 and 30 micrograms kg-1) increased duodenal HCO3- secretion in a dose-dependent fashion. Based on the present findings, we suggest that hypervolaemia increases duodenal HCO3- secretion via release of ANP from the heart.
Jönson
C
C
Department of Physiology, University of Göteborg, Sweden.
Fändriks
L
L
Pettersson
A
A
D000818:Animals; D001062:Appendectomy; D009320:Atrial Natriuretic Factor / Q000008:administration & dosage*; D001639:Bicarbonates / Q000378:metabolism*; D001810:Blood Volume / Q000187:drug effects; D004386:Duodenum / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013153:Splanchnic Nerves / Q000502:physiology; D014630:Vagus Nerve / Q000502:physiology
D001639:Bicarbonates; D009320:Atrial Natriuretic Factor