Effects of copper on T-type Ca2+ channels in mouse spermatogenic cells.
Low voltage-activated, rapidly inactivating T-type Ca2+ channels are found in a variety of cells, where they regulate electrical activity and Ca2+ entry. In whole-cell patch-clamp recordings from mouse spermatogenic cells, trace element copper (Cu2+) inhibited T-type Ca2+ current (IT-Ca) with IC50 of 12.06 microM. Inhibition of IT-Ca by Cu2+ was concentration-dependent and mildly voltage-dependent. When voltage stepped to -20 mV, Cu2+ (10 microM) inhibited IT-Ca by 49.6 +/- 4.1%. Inhibition of IT-Ca by Cu2+ was accompanied by a shift of -2.23 mV in the voltage dependence of steady-state inactivation. Cu2+ upshifted the current-voltage (I-V) curve. To know the change of the gating kinetics of T-type Ca2+ channels, we analyzed the effect of Cu2+ on activation, inactivation, deactivation and reactivation of T-type Ca2+ channels. Since T-type Ca2+ channels are a key component in capacitation and the acrosome reaction, our data suggest that Cu2+ can affect male reproductive function through T-type Ca2+ channels as a preconception contraceptive material.
Lu
Liang
L
Department of Toxicology, Nanjing Medical University, Nangjing, Jiangsu, 210029, People's Republic of China.
Wang
Changsong
C
Gao
Xiaohua
X
Xu
Peng
P
Wang
Jun
J
Wang
Qiang
Q
Cheng
Jie
J
Xiao
Hang
H
D000818:Animals; D020747:Calcium Channels, T-Type / Q000187:drug effects / Q000502:physiology*; D002413:Cations, Divalent; D003300:Copper / Q000494:pharmacology*; D066298:In Vitro Techniques; D015640:Ion Channel Gating; D007700:Kinetics; D008297:Male; D051379:Mice; D018408:Patch-Clamp Techniques; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology*
D020747:Calcium Channels, T-Type; D002413:Cations, Divalent; D003300:Copper