While the function of the ubiquitous Na,K-ATPase alpha1 subunit has been well documented, the role of the sperm-specific alpha4 isoform of this ion transporter is less known. We have explored the importance of alpha4 in rat sperm physiology by taking advantage of the high sensitivity of this isoform for the inhibitor ouabain. Using concentrations that selectively block alpha4 activity, we found...

The acrosome reaction in vertebrate sperm has been shown to be essential for fertilisation [ 11. The process involves fusion and vesiculation of sperm head plasma membranes and the underlying outer acrosomal membrane, resulting in the exocytotic release of acrosomal enzymes. Yanagamachi and Usui have demonstrated that sperm have an absolute requirement for Ca*’ during the acrosome reaction [2]....

Infertility affects one in seven couples who are trying to conceive (Lamb & Lipshultz, 2000; Brugh & Lipshultz, 2004). Decreased semen quality, a measure of the ability of semen to achieve fertilisation, is a primary cause of male infertility. Usually, poor semen quality is characterised by low sperm motility and viability. Assisted reproductive techniques (ART) such as intra-uterine inseminati...

BACKGROUND Sperm length in Drosophilidae varies from a few hundred microns to 6 cm as a result of evolutionary selection. In postcopulatory competition, longer sperm have an advantage in positioning their head closer to the egg. Sperm cell elongation can proceed in the absence of an axoneme, suggesting that a mechanism besides intraflagellar transport emerged to sustain it. RESULTS Here we re...

The sperm maturation and storage functions of the epididymis are important determinants of ejaculate quality, and perhaps provide an avenue to male contraception. In the last 50 years, the creation of epididymal fertility profiles in laboratory animals was followed by recognition of new sperm maturation-related parameters (organization of the acrosome, of the sperm plasmalemma, and -S-S- -based...

A significant percentage of young men are infertile and, for the majority, the underlying cause remains unknown. Male infertility is, however, frequently associated with defective sperm motility, wherein the sperm tail is a modified flagella/cilia. Conversely, a greater understanding of essential mechanisms involved in tail formation may offer contraceptive opportunities, or more broadly, thera...

Sperm capacitation is required for fertilization and involves several ion permeability changes. Although Cl(-) and HCO(3)(-) are essential for capacitation, the molecular entities responsible for their transport are not fully known. During mouse sperm capacitation, the intracellular concentration of Cl(-) ([Cl(-)](i)) increases and membrane potential (Em) hyperpolarizes. As in noncapacitated sp...

Sexual reproduction requires the fusion of sperm cell and oocyte during fertilization to produce the diploid zygote. In mammals complex changes in the plasma membrane of the sperm cell are involved in this process. Sperm cells have unusual membranes compared to those of somatic cells. After leaving the testes, sperm cells cease plasma membrane lipid and protein synthesis, and vesicle mediated t...

This Opinion piece is offered as a cursory overview of sperm development, function, and transport through the eyes of an equine veterinarian. My professional background is predominantly clinical in nature, but my fascination with sperm function and preservation has led to a fairly sizeable review of the scientific literature over the years in hopes of extracting laboratory findings that have ap...