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

• Published in: Biochemical and biophysical research communications Vol. 671; pp. 318 - 326
• Main Authors: López-González, I., Sánchez-Cárdenas, C., De la Vega-Beltrán, J.L., Alvarado-Quevedo, B., Ocelotl-Oviedo, J.P., González-Cota, A.L., Aldana, A., Orta, G., Darszon, A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 03.09.2023
• Subjects: Acrosome - physiology; Acrosome reaction; Acrosome Reaction - physiology; Adenosine Triphosphate; Calcium; Human sperm; Humans; Male; P2X purinergic receptors; Scanning ion conductance microscopy; Semen; Spermatozoa - physiology; NCAP; P4; Iono; Hepes; P2XRs; Acrosome reaction; 5BDBD; Cap; P2X purinergic receptors; Iver; Human sperm; Scanning ion conductance microscopy; HC; ATP
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2023.06.008

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. •External ATP induces a volume increase (ATPVI) in capacitated human sperm heads.•Ivermectin enhances ATPVI and Cu2+, and 5BDBD inhibits it, indicating P2X4Rs contributes to this response.•The ATP-induced acrosome reaction showed the same pharmacological profile as ATPVI.•ATP increased intracellular Ca2+ in 45% of sperm, most of which underwent AR.•P2X4R activation causes ATPVI, putative acrosomal swelling, and results in AR.