Carbachol increases intracellular free calcium concentrations in human granulosa-lutein cells.
We investigated whether the stimulation of human granulosa-lutein cells with muscarinic and nicotinic receptor agonists can cause increases in intracellular free calcium (Ca2+), using Fura-2 microfluorimetry. The addition of carbachol (a non-selective muscarinic and nicotinic receptor agonist) to cultured human granulosa-lutein cells increased intracellular free Ca2+ levels. Concentrations as low as 10 nmol/l were effective. In contrast, nicotine did not evoke elevations of intracellular free Ca2+. Basal Ca2+ levels ranged around 70-140 nmol/l and maximal, carbachol-induced peaks reached 1.1 mumol/l. The carbachol-induced Ca2+ signal was abolished after preincubation of the cells with the muscarinic receptor antagonists quinuclidinyl benzilate or atropine, but it was not affected by removal of extracellular Ca2+. Further evidence for the involvement of intracellular Ca2+ stores is provided by experiments in the absence of extracellular Ca2+. While thapsigargin (a blocker of ATP-driven Ca2+ uptake by intracellular stores) and ionomycin (an ionophore by which Ca2+ is released from intracellular stores) evoked small Ca2+ transients, cells pretreated with these agents did not respond to carbachol any more. These data suggest the presence of a functional muscarinic receptor on human granulosa-lutein cells and imply the involvement of intracellular Ca2+ stores during the cellular response. These results also suggest the participation of the nervous system, acting through muscarinic receptors, in the control of the function of human granulosa-lutein cells.
Mayerhofer
A
A
Abteilung Anatomie und Zellbiologie, Universität Ulm, Germany.
Föhr
K J
KJ
Sterzik
K
K
Gratzl
M
M
D001285:Atropine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology*; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism*; D015759:Ionomycin / Q000494:pharmacology; D008184:Luteal Cells / Q000187:drug effects / Q000378:metabolism*; D009538:Nicotine / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology; D011813:Quinuclidinyl Benzilate / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000378:metabolism; D019284:Thapsigargin
D010936:Plant Extracts; D011976:Receptors, Muscarinic; D015759:Ionomycin; D011813:Quinuclidinyl Benzilate; D019284:Thapsigargin; D009538:Nicotine; D001285:Atropine; D002217:Carbachol; D002118:Calcium