Substance P injected into the medial preoptic area inhibits sodium, potassium and water urinary excretion. Putative modulation of the cholinergic system.
Substance P (SP, 1.5 nmol) injected into the medial preoptic area (MPOA) of conscious, unrestrained, water-loaded male rats induced a significant decrease in urinary sodium, potassium and water excretion. In contrast, a significant natriuretic effect was observed after injection of 0.3 nmol of a specific competitive SP antagonist [( D-Pro2, D-Trp7,9]-substance P). SP partially blocked the carbachol-induced natriuresis in a time-dependent manner. These data indicate a tonic inhibitory action of SP on sodium excretion and suggest a putative modulatory action of SP on the cholinergic system.
Picanço-Diniz
D L
DL
Departamento de Fisiologia, Faculdade de Medicina de Ribeirö Preto, Universidade de São Paulo, Brasil.
Antunes-Rodrigues
J
J
D000818:Animals; D008297:Male; D011188:Potassium / Q000652:urine*; D011301:Preoptic Area / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000652:urine*; D013373:Substance P / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors; D014867:Water / Q000378:metabolism*
D014867:Water; D013373:Substance P; C032132:substance P, prolyl(2)-tryptophan(7,9)-; D012964:Sodium; D011188:Potassium