OBJECTIVE: To evaluate whether gamma-aminobutyric acid receptors are involved in human sperm acrosome reaction induced by the follicular fluid (FF).DESIGN: Random selection of normal sperm samples.SETTING: Normal men in an university clinic of andrology.PATIENT(S): Men with normal sperm analysis parameters.INTERVENTION(S): None.MAIN OUTCOME MEASURE(S): Acrosome reaction on motile spermatozoa.RESULT(S): Follicular fluid stimulated the acrosome reaction dose-dependently. The effect of a maximally effective concentration of FF (30%, vol/vol) was significantly suppressed by bicuculline, a GABAA receptor antagonist, and saclofen, a GABAB receptor antagonist, added concomitantly. Each of the two antagonists used alone was devoid of effect. Because the GABAA receptor is linked to the chloride channel, we tested whether picrotoxin, a blocker of this channel, could modulate the effects of the FF. Picrotoxin alone did not have any effect on the acrosome reaction induced by the FF, whereas it had a significant suppressive effect if coincubated with saclofen. The acrosome reaction induced by the FF was also inhibited by picrotoxin plus verapamil, a calcium channel blocker, whereas verapamil alone had no significant effect. This suggested that both chloride and calcium ions mediated the acrosome reaction induced by the FF.CONCLUSION(S): The simultaneous blockade of GABAA and GABAB receptors suppressed the acrosome reaction induced by the FF. This finding suggested that GABA receptors play a physiologic role in sperm activation and shed further light on the mechanism of FF action on human sperm acrosome reaction.
|Titolo:||Human follicular fluid stimulates the sperm acrosome reaction by interacting with the gamma-amynobutyric acid receptors|
|Data di pubblicazione:||2004|
|Appare nelle tipologie:||1.1 Articolo in rivista|