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

• DOI: 10.1016/j.bbrc.2023.06.008
• Publication Date: 2023-06-03T05:53:04Z
• Authors: I. López-González; C. Sánchez-Cárdenas; J.L. De la Vega-B...; B. Alvarado-Quevedo; J.P. Ocelotl-Oviedo; A.L. González-Cota; A. Aldana; G. Orta; A. Darszon
• Keywords: Acrosome reaction; Capacitation

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.