Determination of the steady-state intracellular chloride concentration in capacitated human spermatozoa.
Chloride channels participate in the mammalian sperm acrosome reaction (AR). However, the mechanism by which sperm regulate intracellular Cl- concentration ([Cl-]i) is not known. The steady-state [Cl-]i has also never been reported for mammalian spermatozoa. Therefore, using chloride-sensitive fluorescent dyes, we sought to determine the steady-state [Cl-]i of capacitated human spermatozoa by a null-point measurement technique. We found that the [Cl-]i was sufficiently elevated (a conservative estimate of > or = 41 mM) such that the opening of chloride channels should result in a Cl- efflux and, hence, in depolarization. Moreover, the [Cl-]i does not remain constant under varying extracellular Cl- concentrations ([Cl-]o).
Garcia
M A
MA
Department of Cell Biology and Human Anatomy, School of Medicine, University of California at Davis, 95616-8643, USA.
Meizel
S
S
D002712:Chlorides / Q000378:metabolism*; D004072:Digitonin / Q000494:pharmacology; D006801:Humans; D008297:Male; D011804:Quinolines / Q000494:pharmacology; D011806:Quinolinium Compounds / Q000494:pharmacology; D013075:Sperm Capacitation; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism*
D002712:Chlorides; D011804:Quinolines; D011806:Quinolinium Compounds; C078229:N-(6-methoxyquinolyl)acetoethyl ester; C070311:6-methoxy-N-ethylquinolinium; D004072:Digitonin