Chemotaxis conclusions

Sperm chemotaxis is a widespread phenomenon. It was discovered in marine species in the mid-1960s, and in the last decade it was also demonstrated in amphibians and mammals. In some of these species— marine species [35, 102], frogs [5], mice [56, 114], rabbits [52], and humans [49, 128]—the evidence for sperm chemotaxis is conclusive. In others, the evidence (if it exists) is still indirect and open to doubt (for a review, see [48]). 

The occurrence of sperm chemotaxis in mammals was established in vitro only at the last decade. As a matter of fact, until then there had been resistance to the concept of mammalian sperm chemotaxis for two main reasons. First, in mammals in which fertilization is internal and very large numbers of spermatozoa are ejaculated directly into the female reproductive tract (4 0X10 in humans [185] 10 -10 in mammals in general [66]), chemotaxis was believed to be unnecessary because a sufficient number of spermatozoa would reach the egg coincidentally. Second, technical difficulties in studying mammalian sperm chemotaxis prevented the acquisition of conclusive evidence. The primary technical difficulty was a very low signal-to-noise ratio in the measurements, resulting from the fact that only a small fraction of the sperm... 

In conclusion, follicular fluid, bourgeonal, ANP, and RANTES are the only substances that have been demonstrated to act as chemoattractants for spermatozoa by assays that differentiate between chemotaxis and other processes causing accumulation (Table 1). ANP may not be a direct physiological chemoattractant but rather a guanylate cyclase activator. The significance of sperm chemotaxis to bourgeonal and RANTES is an open question. The identity of the chemoattractant(s) in follicular fluid has yet to be revealed. 

The studies cited in this paper show that for n-aliphatic alcohols (C1-C12) and -acids (C2 Cg), olfaction and taste act in similar ways as chemotaxis and anesthesia. Jain et al. ( ) came to a similar conclusion for many other membrane systems. Alcohols and fatty acids were used in the present study since olfactory and gustatory data on these compounds could be compared with those on many other systems. It should be kept in mind that threshold... 

---