Table 2.

The main types of ion channels and related proteins in the reproductive system. Numbers in brackets indicate the references.

Type of Ion Channel	Type of Protein	Location	Function
Porins	VDAC1, 2, 3	Sertoli cells [162]; GV (germinal vesicle) and MII (meiosis II) stage porcine oocytes [137] outer dense fibers of the bovine sperm flagellum; head of bovine sperm, late spermatocytes, spermatids and spermatozoa of the bovine testis [161]; GV (germinal vesicle) and MII (meiosis II) stage porcine oocytes [137]; mouse granulosa cells [197] outer dense fibers of the bovine sperm flagellum in porcine [161];	participation in follicular development and autophagy suppression to folliculogenesis in mammals [197]; deficient males are infertile because of structural abnormalities in the sperm tail, leading to sperm immotility [198]
Cation channels sperm associated	CATSPER1, 2, 3, 4	Plasma membrane of the sperm tail [144] testis [199]	key role in the motility, hyperactivation and fertilization function of sperm [141,200]
Inositol trisphosphate receptor	InsP3R1, 2,3	human GCS [146] mouse oocyte [201]	proper fertilization [148]
	CFTR	rat epididymal epithelial cells [174]; porcine vas deferens epithelial cells [202]; vagina, cervix, uterus and fallopian tubes, in rodents and humans [153,203,204]; mouse endometrial cells [205]	CFTR plays a key role in regulating Cl− secretion, and thus fluid volume in male and female reproductive tract [152,202]; sperm capacitation [206]
Gap junction protein	Cxs	mouse, human, rat, pig, dog seminiferous tubules [190]; mouse, human, swine, bovine, canine ovary [207,208,209,210]; oocyte and granulosa cells (GCs) [171,211]; human, mouse and baboon endometrium [170,212]	function as nurturing the germ cell lineage; developmental competence by oocyte, communication with cumulus oophorus cells; connection between GCs population, mural—mural GCs communication; folliculogenesis [213,214]