Reversible inhibition of the motility of human spermatozoa by cytochalasin B.

Cytochalasin B inhibits the motility and metabolism of washed human spermatozoa at low concentrations (20 to 200 mum). Spermatozoal motility (primarily the frequency of flagellar contraction) declines slowly after addition of the antibiotic but is not abolished even after treatment for several hours. The addition of caffeine or dibutyrylcyclic adenosine 3' :5'-monophosphate to washed sperm suspensions increases the percentage of motile cells, the frequency of flagellar contraction, and the rate of glycolysis. These effects are blocked by cytochalasin B. However, cytochalasin B-treated spermatozoa regain their responsiveness to these agents when the antibiotic is washed out of supporting media. These effects are discussed in terms of an interaction of cytochalasin B with the sperm plasma membrane.