Stimulatory effect of enkephalins on calcium efflux from bovine adrenal chromaffin cells in culture.
The effects of leucine- and methionine-enkephalin, opiate peptides, on Ca2+ efflux from cultured bovine adrenal chromaffin cells were examined. These enkephalins stimulated the efflux of 45Ca2+ from cells in a concentration-dependent manner (10(-8) M-10(-6) M). Leucine-enkephalin did not increase the intracellular free Ca2+ level, 45Ca2+ uptake, catecholamine secretion, cAMP level or cGMP level. The peptide-stimulated 45Ca2+ efflux was not inhibited by incubation in Ca2+-free medium, but was inhibited by incubation in Na+-free medium. These results indicate that enkephalins stimulate extracellular Na+-dependent 45Ca2+ efflux from cultured bovine adrenal chromaffin cells, probably by stimulating membrane Na+/Ca2+ exchange.
Umeda
T
T
Department of Pharmacy, School of Medicine, The University of Tokushima, Japan.
Azuma
M
M
Houchi
H
H
Ikehara
T
T
Shono
F
F
Yoshizumi
M
M
Tamaki
T
T
Minakuchi
K
K
D000313:Adrenal Medulla / Q000166:cytology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D002395:Catecholamines / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000187:drug effects / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004743:Enkephalin, Leucine / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000494:pharmacology; D004745:Enkephalins / Q000494:pharmacology*; D005456:Fluorescent Dyes; D016257:Fura-2
D002132:Calcium Radioisotopes; D002395:Catecholamines; D004745:Enkephalins; D005456:Fluorescent Dyes; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D000242:Cyclic AMP; D006152:Cyclic GMP; D002118:Calcium; D016257:Fura-2