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Emerging Concepts in Ion Channel Biophysics
Poster Abstracts
43
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.