T-type Ca2+ channels in sperm function

Intracellular Ca2+ regulates many fundamental physiological processes in excitable and non-excitable cells. Certainly this is the case of sperm where the local concentration of intracellular Ca2+ ([Ca2+]i) is significantly influenced by Ca-2+, permeable channels present in the cell channels (Ca-V) of the T-type (Ca(V)3) appear to have an eminent role plasma membrane. Amongst these channels, the voltage dependent Ca2+ in the acrosome reaction (AR) of some sperm species, though they may participate in other important functions like motility and capacitation. The AR is an exocytotic event where the acrosome vesicle in the posterior region of the head fuses with the plasma membrane. This reaction allows sperm to fuse and fertilize the egg. Here we summarize our present knowledge regarding Ca(V)3 channels in sperm, show the first direct electrophysiological evidence for their presence in maturing mouse sperm and discuss some of the relevant unanswered questions. (c) 2006 Elsevier Ltd. All rights reserved.