Circadian rhythms of acid secretion and electric parameters in rat gastric mucosa in vitro.
In male Wistar rats standardized from birth in LD 12:12 conditions (with light from 0700 to 1900 hr), samples of mucosa from the body of the stomach were isolated in vitro and mounted in a Ussing-type chamber. Spontaneous secretion of the hydrogen ion (H+)during 45 min of incubation was measured. Some electric parameters [transmucosal potential difference (PD) and electrical resistance (R)] were detected in the gastric mucosa both during H+ secretion and during inhibition of acid secretion by cimetidine. The variables studied were analyzed with the single cosinor method, and all revealed a circadian rhythm with acrophases during the dark span. The higher values of PD and R found during the dark hours are unrelated to acid secretion and may indicate a greater efficiency of ionic pumps and a limited passive permeability.
D000818:Animals; D002927:Cimetidine / Q000494:pharmacology; D002940:Circadian Rhythm; D004553:Electric Conductivity; D004594:Electrophysiology; D005744:Gastric Acid / Q000378:metabolism*; D005753:Gastric Mucosa / Q000502:physiology*; D008027:Light; D008297:Male; D008938:Mitosis; D051381:Rats; D011919:Rats, Inbred Strains
D002927:Cimetidine