Inhibition of Ca2+ mobilization by caffeine in a cultured vascular smooth muscle cell line (A7r5).
The effects of caffeine on the resting level and agonist-induced changes in intracellular calcium ([Ca2+]i) have been studied in the vascular smooth muscle cell line A7r5. Caffeine (1-30 mM) lowers the resting [Ca2+]i by reducing the entry of Ca2+ and inhibits completely the mobilization of Ca2+ by arginine vasopressin. Application of forskolin, to elevate cAMP, does not affect the resting level of Ca2+i but does abolish the agonist-induced rise. These data add to the complexity of caffeine-induced changes in [Ca2+]i and point to a possible interaction between cAMP and other second messenger systems mobilizing Ca2+i in this cell type.
Otun
H
H
Department of Obstetrics and Gynaecology, Medical School, The University, Newcastle upon Tyne.
Gillespie
J I
JI
Greenwell
J R
JR
Dunlop
W
W
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D002110:Caffeine / Q000494:pharmacology*; D002118:Calcium / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D016257:Fura-2 / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D051381:Rats
D001127:Arginine Vasopressin; D005576:Colforsin; D002110:Caffeine; D002118:Calcium; D016257:Fura-2