ATP increases head volume in capacitated human sperm via a purinergic channel

Biochem Biophys Res Commun. 2023 Sep 3:671:318-326. doi: 10.1016/j.bbrc.2023.06.008. Epub 2023 Jun 3.

Abstract

Scanning ion-conductance microscopy allowed us to document an external Ca2+ dependent ATP driven volume increase (ATPVI) in capacitated human sperm heads. We examined the involvement of purinergic receptors (PRs) P2X2R and P2X4R in ATPVI using their co-agonists progesterone and Ivermectin (Iver), and Cu2+, which co-activates P2X2Rs and inhibits P2X4Rs. Iver enhanced ATPVI and Cu2+ and 5BDBD inhibited it, indicating P2X4Rs contributed to this response. Moreover, Cu2+ and 5BDBD inhibited the ATP-induced acrosome reaction (AR) which was enhanced by Iver. ATP increased the concentration of intracellular Ca2+ ([Ca2+]i) in >45% of individual sperm, most of which underwent AR monitored using FM4-64. Our findings suggest that human sperm P2X4R activation by ATP increases [Ca2+]i mainly due to Ca2+ influx which leads to a sperm head volume increase, likely involving acrosomal swelling, and resulting in AR.

Keywords: Acrosome reaction; Human sperm; P2X purinergic receptors; Scanning ion conductance microscopy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrosome / physiology
  • Acrosome Reaction / physiology
  • Adenosine Triphosphate
  • Calcium
  • Humans
  • Male
  • Semen*
  • Spermatozoa* / physiology

Substances

  • Adenosine Triphosphate
  • Calcium