Analysis of Ca2+ currents in spermatocytes from mice lacking Cav2.3 (α1E) Ca2+ channel

In mammalian male germ-line cells, low-voltage-activated (LVA) Ca2+ current has been identified and its electrophysiological properties have been studied. To investigate whether alpha (1)2.3 (alpha (1E)) subunit of the voltage-dependent Ca2+ channel codes for the LVA current, whole-cell patch clamp and following reverse transcription-polymerase chain reaction (RT-PCR) experiments were performed in pachytene spermatocytes from Ca(v)2.3+/+ and Ca(v)2.3-/- mice. Whole-cell current in acutely dissociated pachytene spermatocytes from Ca(v)2.3+/+ and Ca(v)2.3-/- mice displayed a typical profile of LVA Ca2+ currents and kinetics with no significant differences. Single-cell RT-PCR revealed the expression of Cacna1g in the pachytene spermatocytes from Ca(v)2.3+/+ and Ca(v)2.3-/- mice in which LVA Ca2+ currents were actually recorded. These results suggest that the Ca(v)2.3 channel makes no detectable contribution to the LVA Ca2+ current in the pachytene spermatocyte. Instead, Ca(v)3 family such as Ca(v)3.1 may be the likely candidates responsible for the LVA currents in pachytene spermatocytes. (C) 2001 Academic Press.