Influence of the muscarinic agonist carbachol on intracellular Ca2+ in chicken granulosa cells: I. Dependence on follicular maturation.
The present study addressed the influence of follicular development on carbamylcholine chloride (Cch)-induced Ca2+ transients and inositol 1,4,5-trisphosphate (IP3) production in granulosa cells isolated from the first (F1), third (F3), and fifth and sixth (F5,6) largest follicles. Intracellular free calcium, [Ca2+]i, was measured in fura-2-loaded cells about 20-36 h after their isolation. The percentage of cells responding to a maximal stimulatory concentration of Cch (0.2 mM) was higher in the F1 (89%) granulosa cells than in cells from the F3 (68%) and the F5,6 (72%) follicles. Most of the Ca2+ transients that were elicited in F1 granulosa cells were characterized by large (696 +/- 119 nM), fast (260 +/- 55 nM/sec) increases in [Ca2]i followed by a slow, uneven decrease in [Ca2+]i to the resting concentration. In contrast, Cch-induced changes in [Ca2+]i in F3 and F5,6 granulosa cells were generally both smaller (154 +/- 37 nM and 165 +/- 37 nM, respectively) and slower (36 +/- 25 nM/sec and 46 +/- 16 nM/sec, respectively) than those observed in cells from the largest follicle. Removal of external Ca2+ did not alter the large, fast increases in [Ca2+]i; however, it nearly blocked the slow responses observed in F3 and F5,6 cells. IP, production was elevated in 3H-myo-inositol-loaded F1 granulosa cells after 1 min of Cch (0.2 mM) treatment, whereas inositol bisphosphate (IP2) production and inositol monophosphate (IP) production were elevated only after longer incubations.(ABSTRACT TRUNCATED AT 250 WORDS)
Soboloff
J
J
Reproductive Biology Unit, Loeb Medical Research Institute, Ottawa Civic Hospital, Ontario, Canada.
Wade
M G
MG
Wells
G
G
Désilets
M
M
Tsang
B K
BK
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology*; D002478:Cells, Cultured; D002645:Chickens; D004533:Egtazic Acid / Q000494:pharmacology; D005260:Female; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D015544:Inositol 1,4,5-Trisphosphate / Q000096:biosynthesis; D007295:Inositol Phosphates / Q000096:biosynthesis; D007700:Kinetics; D008345:Manganese / Q000494:pharmacology; D006080:Ovarian Follicle / Q000502:physiology*
D007295:Inositol Phosphates; D008345:Manganese; D004533:Egtazic Acid; D015544:Inositol 1,4,5-Trisphosphate; D002217:Carbachol; D002118:Calcium