Calcium signaling in human spermatozoa.

DE BLAS, G.; BRANHAM, M.T; TREVINO, CL; SOLIS A; TOMES, CN; MAYORGA, LS; DARSZON, A.

Congreso; 48º SAIB; 2012

SAIB

Calcium and cAMP signaling plays a pivotal role in sperm physiology, being intimately involved in the regulation of capacitation, hyperactivation and acrosome reaction. In a previous report we have proposed that the cAMP analogue 8-(pchlorophenylthio)-2'-O-methyladenosine-3', 5'-cyclic monophosphate (8-pCPT-2'-O-Me-cAMP) elicits intracellular calcium release in human sperm. Intracellular calcium stores play a central role in the regulation of cellular [Ca2+]i and in the generation of complex [Ca2+] signals such as oscillations and waves. The aim of this study was to investigate the calcium stores and calcium channels involved in the 8-pCPT-2'-O-Me-cAMP pathway in human spermatozoa. We used real time dynamic assays - with high speed and spatial resolution- and fluorescent calcium sensors. To asses this, capacitated human sperm were loaded with Fluo3-AM, then incubated in a calcium-free medium and treated with different agonist of the AR (8-pCPT-2'-O-Me-cAMP, progesterone and recombinant human ZP3). We found that all AR inducers triggered spatial distribution of Ca2+and using a kinetic assay we studied the dynamics and direction of the calcium wave. Our results indicate that 8-pCPT-2'-O-Me-cAMP, progesterone and ZP3 induce a calcium wave that starts in the posterior neck region and propagates to the acrosome region.