Functional Analysis of Transmembrane Ion Flux and Transport in Sperm

In the last decade, to extend our knowledge of the biological basis of male infertility, a series of functional tests have been developed to assess the competence of spermatozoa to carry out the fundamental processes essential to conception. New and emerging technologies have shown that sperm function, and hence fertilization, is orchestrated by a unique set of mostly sperm-specific ion channels, transporters, and exchangers, such as CatSper and Slo3. The present review paper reports the current knowledge on the strategies for identifying damaged transporters and ion exchangers. In addition, the main available functional tests of transmembrane ion flux and transport in sperm for the diagnosis of infertility are examined, with particular regard to the interest in evaluating sperm ion channel methods. The laboratory protocols for some of them are also described in detail. To complete the state of knowledge, two clinical scenarios involving patients with mutations of the CatSper gene were also illustrated.