Emerging Concepts in Ion Channel Biophysics

Emerging Concepts in Ion Channel Biophysics

Poster Abstracts

13-POS Board 13 Non-genomic Steroid Signalling in Human Sperm Christoph Brenker , Timo Strünker. University of Münster, Münster, Germany.

Human sperm have to fulfil a series of demanding functions during fertilization: they navigate along various chemical and physical cues to localize the oocyte, and they break through its protective vestments by hyperactivation and acrosomal exocytosis. These processes are controlled by changes in intracellular pH (pH i ), membrane potential (V m ), and intracellular Ca 2+ concentration ([Ca 2+ ] i ), mediated by a subset of unique ion channels. The sperm-specific ion channels CatSper and Slo3 serve as central signalling nodes and control [Ca 2+ ] i and V m . Steroids released by the oocyte complex regulate the function of these ion channels and thereby sperm behaviour. Here we show by electrophysiological recordings from human sperm how steroids differentially affect these ion channels. Using Ca 2+ and V m fluorimetry we studied how this modulation of ion channel function affects sperm signalling and thereby sperm function. Moreover we identified synthetic steroidal ligands that regulate ion channel function and will discuss their mechanism of action.

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