Discovery: Studying Sperm for Male Contraception
In a breakthrough study, scientists from University of California, San Francisco, have identified a mechanism that prompts the male sperm to start swimming to reach and fertilize egg.
The research has led to the discovery of new target for male contraception.
The sperm’s motility is short lived. When in the male reproductive tract they have to rest easy, lest they wear themselves out prematurely and give up any chance of ever finding an egg.
Though sperm are generally considered pretty wriggly little guys, before they are launched into action, so to speak, they aren’t racing around. While researchers have long known that what gets them swimming is a change in internal pH level—the more alkaline their pH, the more aggressively they swim—until now, the mechanism by which sperm rapidly drop protons, which changes their pH from acidic to alkaline, wasn’t clear. According to this new study, published in the journal Cell, sperm are equipped with tons of tiny little pores that, when open, enable them to release protons and get a move on.
These pores—or Hv1 proton channels, as the team of researchers from the University of California, San Francisco, refer to them—swing open in a variety of environments, including when external pH becomes more alkaline or when sperm are exposed to the chemical anandamine, found in both female and male reproductive systems. Researchers say that anandamine may be particularly concentrated closer to the egg, giving sperm that extra, em, encouragement at a critical point in their journey. Gaining a better understanding of what prompts sperm to spring into action could open doors toward developing effective male contraception, or, alternatively, ways to give “slow swimmers” a jolt.
In addition to possibilities for birth control or fertility enhancement, this research may also help shed light on how marijuana decreases male fertility. Anandamine is an endocannibanoid, or basically, the body’s own natural version of the main ingredient—cannibanoids—found in marijuana. If marijuana tricks sperm into acting as though they’re being called to action, then they may prematurely start swimming, tiring themselves out before they’ve made much progress, the researchers speculate.
Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield, said: “Although it seems obvious that sperm have to swim in order to find and fertilise an egg inside the female body, or in the dish during IVF, we are only just uncovering some of the molecular details that the sperm use when swimming”
“Now that we know what this ion channel is, then it could lead us to either develop a novel contraceptive for men, or perhaps find a way to improve the sperm motility for men whose sperm don’t swim as well as they should”
