Sperm Guidance in Mammals: II. Thermotaxis
At ovulation, at least in rabbits (Bahat et al., 2005; David et al., 1972) and pigs (Hunter and Nichol, 1986), a temperature difference of 1–2°C is established within the oviduct, the temperature being higher at the fertilization site than at the junction between the uterus and the oviduct, close to the sperm storage site in the oviduct (Suarez, 2002). This difference is formed by a time-dependent temperature drop at the uterus-oviduct junction, a drop that occurs in spite of the simultaneous rise in body temperature at ovulation (Bahat et al., 2005). Following the suggestion of Hunter (1998) that this temperature difference might serve as a cue for guiding spermatozoa to the site of fertilization, Bahat et al. (2003) demonstrated that rabbit and human spermatozoa are able to sense small temperature differences and respond to them by thermotaxis. The temperature gradient in the rabbit oviduct was calculated to be at the order of 0.1°C/cm (Bahat and Eisenbach, 2006), within the range of known thermotaxis systems. As in sperm chemotaxis, only capacitated spermatozoa are thermotactically responsive (Bahat et al., 2003).
Read more about this topic: Sperm Guidance
Famous quotes containing the word guidance:
“If Los Angeles has been called “the capital of crackpots” and “the metropolis of isms,” the native Angeleno can not fairly attribute all of the city’s idiosyncrasies to the newcomer—at least not so long as he consults the crystal ball for guidance in his business dealings and his wife goes shopping downtown in beach pajamas.”
—For the State of California, U.S. public relief program (1935-1943)