Veratridine-sensitive Na channels regulate human sperm fertilization capacity.

Aims: The sperm plasma membrane contains specific ion channels and transporters that initiate changes in Ca, Na, K and H ions in the sperm cytoplasm. Ion channels are key regulators of the sperm membrane potential, cytoplasmic Ca and intracellular pH (pH), which leads to regulate motility, capacitation, acrosome reaction and other physiological processes crucial for successful fertilization. Expression of epithelial sodium channels (ENaC) and voltage-gated sodium channels (Na) in human spermatozoa has been reported, but the role of Na fluxes sodium channels in the regulation of sperm cell function remains poorly understood.

Expression of neurokinin B/NK3 receptor and kisspeptin/KISS1 receptor in human granulosa cells.

Study Question: Are neurokinin B (NKB), NK3 receptor (NK3R), kisspeptin (KISS1) and kisspeptin receptor (KISS1R) expressed in human ovarian granulosa cells?

Summary Answer: The NKB/NK3R and kisspeptin/KISS1R systems are co-expressed and functionally active in ovarian granulosa cells.

What Is Known Already: The NKB/NK3R and KISS1/KISS1R systems are essential for reproduction. In addition to their well-recognized role in hypothalamic neurons, these peptide systems may contribute to the control of fertility by acting directly on the gonads, but such a direct gonadal role remains largely unknown.

The voltage-gated sodium channel nav1.8 is expressed in human sperm.

The role of Na(+) fluxes through voltage-gated sodium channels in the regulation of sperm cell function remains poorly understood. Previously, we reported that several genes encoding voltage-gated Na(+) channels were expressed in human testis and mature spermatozoa. In this study, we analyzed the presence and function of the TTX-resistant VGSC α subunit Nav1.

Differentially regulated expression of neurokinin B (NKB)/NK3 receptor system in uterine leiomyomata.

Study Question: Are the vasoactive peptide neurokinin B (NKB) and its preferred NK3 receptor (NK3R) differentially expressed in leiomyomas compared with normal myometrium?

Summary Answer: In leiomyomas, NKB is up-regulated and delocalized, while its preferred NK3R is also differentially regulated.

What Is Known Already: The expression of NKB/NK3R in the central nervous system is essential for proper function of the human reproductive axis. Additionally, this system is also widely expressed throughout the female genital tract.

Autocrine regulation of human sperm motility by the met-enkephalin opioid peptide.

Objective: To verify the presence of protein precursor pro-enkephalin (PENK) and met-enkephalin in human spermatozoa and to characterize the effects of exogenous and endogenous enkephalins on sperm motility.

Design: We carried out expression assays for met-enkephalin and its protein precursor PENK by reverse transcription-polymerase chain reaction (RT-PCR), Western blot, and immunofluorescence techniques in sperm cells and motility analysis after incubation of semen samples with met-enkephlin enzyme inhibitors and the opioid receptor antagonist naloxone. Met-enkephalin secretion was analyzed by flow cytometry.