Analysis of vasopressin-induced Ca2+ increase in rat hepatocytes.
To analyze vasopressin-induced Ca2+ increase in liver cells, rat hepatocytes were isolated and attached to collagen-coated cover slips. Using fura-2, a Ca2+-sensing dye, changes in intracellular Ca2+ concentration by vasopressin were monitored. Results in this communication suggested that vasopressin-induced Ca2+ increase were composed of both Ca2+ release from internal Ca2+ stores and influx from the plasma membrane. The Ca2+ influx consisted of two distinguishable components. One was dependent on the presence of vasopressin and the other was not. SK&F96365 blocked vasopressin-induced Ca2+ influx in a dose-dependent manner. Vasopressin-induced Ca2+ release from internal stores diminished in a primary culture of hepatocytes according to the culture time. However, changes in vasopressin-induced Ca2+ influx across the plasma membrane differed from changes in the Ca2+ release from internal stores, suggesting two separate signalings from receptor activation to internal stores and to the plasma membrane.
Kim
Hyun-Sook
HS
Laboratory of Pharmacology College of Pharmacy, Pusan National University, Busan, 609-735, Korea.
Okajima
Fumikazu
F
Im
Dong-Soon
DS
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism; D002478:Cells, Cultured; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015854:Up-Regulation / Q000187:drug effects* / Q000502:physiology*; D014667:Vasopressins / Q000494:pharmacology*
D015220:Calcium Channels; D007093:Imidazoles; D014667:Vasopressins; C063159:1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole; D002118:Calcium