Year: 1992
Type: article
Abstract: : Unlike those of many mammals, rat and hamster spermatozoa do not appear to be fully activated at ejaculation. Most rat spermatozoa transported en masse to the uterus approximately 2 minutes after coitus were vigorously motile on recovery soon thereafter in uterine fluid, whereas a majority, and sometimes all, were immotile in samples collected less than 2 minutes after coitus from the anterior vagina of normal females and up to 15 minutes after coitus from the anterior vagina in females with obstructed cervices. Many of these immotile rat vaginal spermatozoa began instant vigorous movement upon exposure to Tyrode's solution or uterine fluid. Hamster spermatozoa recovered from the vagina about 2 minutes after coitus were also immotile or displayed only slow, languid serpentine movements, but that motility profile remained very similar in spermatozoa taken 0.5 hours to 6 hours after coitus from the uterus, which is essentially fluid‐free in the hamster. In the hamster, actively motile spermatozoa were evident only in the isthmus of the (transilluminated) oviduct. As in the rat, immotile vaginal and uterine hamster spermatozoa instantly began vigorous progressive motility in vitro on contact with Tyrode's solution or rat uterine fluid. Immotile spermatozoa from the rat and hamster cauda epididymidis immediately became highly motile in Tyrode's solution, and they developed a somewhat less rapid flagellar beat in 150 mmol/L NaCI or KCI, with or without 2mmol/L CaCI2. In contrast, dilution with an isotonic sucrose solution containing no ions, or only 2mmol/L CaCI2, evoked very slow and transient movement of rat and hamster epididymal sperm tails. We conclude that uterine fluid is a primary activating agent of sperm motility in the rat, whereas in the hamster active motility first develops only in the oviduct. The motility initiation factors in the female reproductive tract of the rat and hamster appear to be nonspecific. In vitro observations confirm that, although dilution of epididymal immobilin in which spermatozoa are enmeshed may play some minor part in initiating motility, other elements, including monovalent cations, are the major stimulus for the initiation of epididymal sperm motility in these species.
Source: Journal of Andrology
Authors: J. MICHAEL BEDFORD, RYUZO YANAGIMACHI
Language: English
Subfield: Reproductive Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W1535739843