Influence of extracellular ATP on mammalian sperm physiology.

In addition to its central role in cellular metabolism, adenosine 5′-triphosphate (ATP) is an important extracellular signalling molecule involved in various physiological processes. In reproduction, extracellular ATP participates in both autocrine and paracrine paths regulating gametogenesis, gamete maturation and fertilisation. This review focusses on how extracellular ATP modulates sperm physiology with emphasis on the mammalian acrosome reaction. The presence of extracellular ATP in the reproductive tract is primarily determined by the ion channels and transporters that influence its movement within the cells comprising the tract. The main targets of extracellular ATP in spermatozoa are its own transporters, particularly species-specific sperm purinergic receptors. We also discuss notable phenotypes from knock-out mouse models and human Mendelian inheritance related to ATP release mechanisms, along with immunological, proteomic, and functional observations regarding sperm purinergic receptors and their involvement in sperm signalling. Reproductive systems express different ion channels and transporters that release ATP into their lumens, which may regulate sperm physiology. Epididymal ATP has been suggested to influence basal sperm motility. Oviductal ATP triggers a head sperm volume increase which contributes to acrosome reaction. Image by López-González, I. This article belongs to the Collection Dedication to Jim Cummins. [ABSTRACT FROM AUTHOR]