Micropuncture studies of the motility of rete testis and epididymal spermatozoa.

The effect of cyclic adenosine 3':5'-monophosphate (cAMP) and caffeine on the motility of spermatozoa obtained in vivo by micropuncture from the rat rete testis, caput epidiymidis, and cauda epididymidis was studied. Spermatozoa from all sites were immobile in their native fluid. Rete testis spermatozoa were not motile under any experimental conditions. After dilution in salt solution, some caput sperm exhibited circular motion, whereas most cauda sperm swam progressively. Dextrose enhanced the motility of sperm from both epidiymal sites. Caffeine further increased the motility of epididymal sperm. Dibutyryl cAMP and cAMP stimulated caput spermatozoa but had no effect on cauda spermatozoa.