[The transducing pathway of Ca2+ influx during progesterone-initiated acrosome reaction of guinea pig sperm].
Progesterone and gamma-aminobutyric acid (GABA) could initiate the acrosome reaction (AR) in guinea pig spermatozoa, which was independent of extracellular Cl- in vitro, and a potentiation effect between progesterone and GABA was demonstrated. Antagonists of GABAA receptor/Cl- channel, picrotoxin and bicuculline, have no effect on the progesterone-induced AR, but they can significantly inhibit the GABA-induced AR in (Cl-)-containing medium. While in (Cl-)-deficient medium, picrotoxin has significant inhibitory effect on both progesterone- and GABA-induced AR, both progesterone- and GABA-induced AR are inhibited by the Ca2+ channel blocker, nifedipine. These results suggest that a GABAA/Cl- receptor complex and a Ca2+ channel might be involved in the influx of extracellular Ca2+ during the progesterone-induced AR.
Jia
Z Y
ZY
Zhejiang Academy of Medical Sciences, Hangzhou.
Yuan
Y Y
YY
Shi
Q X
QX
D000177:Acrosome / Q000187:drug effects*; D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D002478:Cells, Cultured; D006168:Guinea Pigs; D008297:Male; D011374:Progesterone / Q000494:pharmacology*; D013094:Spermatozoa / Q000166:cytology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D015220:Calcium Channels; D011374:Progesterone; D005680:gamma-Aminobutyric Acid; D002118:Calcium