The CatSper channel modulates boar sperm motility during capacitation

Reprod Biol. 2017 Mar;17(1):69-78. doi: 10.1016/j.repbio.2017.01.001. Epub 2017 Jan 8.

Abstract

The cation channel of sperm (CatSper) comprises four transmembrane subunits specifically expressed in human, equine, murine and ovine spermatozoa, apparently implicated in capacitation, hyperactivation and acrosome exocytosis. Western blotting and immunocytochemistry showed hereby that CatSper subunits are also present in boar spermatozoa, primarily over the sperm neck, tail and cytoplasmic droplets; albeit CatSper -1 presented in addition some distribution over the membrane of the acrosome and CatSper -2 and -4 over the membrane of the post-acrosome. The role of the Catsper channel in boar spermatozoa was investigated by extending the spermatozoa in media containing different calcium (Ca2+) availability and exposure to the capacitation-trigger bicarbonate, to progesterone or CatSper inhibitors (Mibefradil and NNC 55-0396), separately or sequentially, at physiological and toxicological doses. Extracellular Ca2+ availability, combined with bicarbonate exposure (capacitation-inducing conditions) decreased sperm motility, similarly to when spermatozoa incubated in capacitation-inducing conditions was exposed to Mibefradil and NNC 55-0396. Exposure of these spermatozoa to progesterone did not cause significant changes in sperm motility and nor did it revert its decrease induced by CatSper antagonists. In conclusion, the CatSper channel regulates sperm motility during porcine capacitation-related events in vitro.

Keywords: Boar; Capacitation; CatSper; Sperm motility; Spermatozoa.

MeSH terms

  • Acrosome / drug effects
  • Acrosome / metabolism*
  • Animals
  • Benzimidazoles / pharmacology
  • Calcium Channel Blockers / pharmacology
  • Calcium Channels / chemistry
  • Calcium Channels / metabolism*
  • Calcium Signaling / drug effects
  • Cyclopropanes / pharmacology
  • Hydrolases / metabolism
  • Intracellular Membranes / drug effects
  • Intracellular Membranes / metabolism*
  • Male
  • Mibefradil / pharmacology
  • Microscopy, Confocal
  • Naphthalenes / pharmacology
  • Progesterone / metabolism
  • Protein Subunits / antagonists & inhibitors
  • Protein Subunits / metabolism
  • Protein Transport / drug effects
  • Sodium Bicarbonate / metabolism
  • Sperm Capacitation* / drug effects
  • Sperm Motility / drug effects
  • Spermatozoa / cytology
  • Spermatozoa / drug effects
  • Spermatozoa / physiology*
  • Sus scrofa / physiology*
  • Sweden

Substances

  • Benzimidazoles
  • Calcium Channel Blockers
  • Calcium Channels
  • Cyclopropanes
  • Naphthalenes
  • Protein Subunits
  • NNC 55-0396
  • Mibefradil
  • Progesterone
  • Sodium Bicarbonate
  • Hydrolases