Effects of propranolol and caffeine on movement characteristics of human sperm

Human sperm, separated on Percoll gradients and transferred to cell culture medium, were exposed to various concentrations of propranolol (0.8-800 microM) or caffeine (3 microM-17 mM) for 4 h. Their motility pattern was analysed after 5 min and 4 h, employing the computerized Cellsoft system. Curvilinear velocity (VCL), percentage motile sperm, linearity (LIN), mean amplitude of lateral head displacement (ALHMEAN) and beat cross-frequency (BCF) were assessed. Both drugs had a practically immediate effect on the sperm. Propranolol concentrations greater than 80 microM had a negative effect on all movement variables, except VCL and ALHMEAN, which showed a slight, non-significant, initial increase. LIN and the percentage motile sperm appeared to be somewhat negatively affected at lower concentrations (80 microM) than the other variables, and were reduced further at higher concentrations and with time. The presence of 800 microM propranolol immobilized all sperm within 4 h. Caffeine at 1.7 and 5 mM, increased VCL and ALHMEAN. In contrast, the highest caffeine concentration tested (17 mM) had a negative effect on all variables at 4 h after addition.