Dopamine-dependent inhibition of jejunal Na+-K+-ATPase during high-salt diet in young but not in adult rats

• Type: Article in International Scientific Journal
• Date: 1998

Authors

vieira-coelho, ma (Author) Other; Teixeira, VAL (Author) Other; Finkel, Y (Author) Other; soares-da-silva, p (Author) FMUP; Bertorello, AM (Author) Other

Journal

Title: American Journal of Physiology - Gastrointestinal and Liver Physiology

Vol. 275

Pages: G1317-G1323

ISSN: 0193-1857

Publisher: American Physiological Society

Indexing

ISI Web of Knowledge - 43 Citations

Scopus - 50 Citations

Other information

Authenticus ID: P-001-6JZ

Abstract (EN): During high-salt diet endogenous dopamine (DA) reduces jejunal sodium transport in young but not in adult rats. This study was designed to evaluate whether this effect is mediated, at the cellular level, by inhibition of Na+-K+-ATPase activity. Enzyme activity was determined in isolated jejunal cells by the rate of [gamma-P-32]ATP hydrolysis. Cells were obtained from weanling and adult rats fed either with high- or normal-salt diet. In 20-day-old but not in 40-day-old rats Na+-K+-ATPase activity was significantly reduced during high-salt diet. This inhibition was abolished by a blocker of DA synthesis. The decreased activity was associated with a decreased alpha(1)-subunit at the plasma membrane. During high-salt diet there was an increase in DA content in jejunal cells from 20-day-old rats, associated with a parallel decrease in 5-hydroxytryptamine compared with normal-salt diet. In 40-day-old rats, however, the catecholamine level remained unchanged during high-salt diet. Incubation of isolated jejunal cells with DA resulted in a dose-dependent inhibition of Na+-K+-ATPase activity in 20- but not in 40-day-old rats. We conclude that during high-salt diet, jejunal Na+-K+-ATPase in 20-day-old rats is inhibited, and this effect is likely to be mediated by locally formed DA.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7