Localized reactivation of the principal piece of demembranated hamster sperm by iontophoretic application of ATP.

Mature hamster sperm were demembranated with Triton X-100, and the principal piece of the flagellum was reactivated by iontophoretic application of ATP. The response was a brief local straightening of a short length of the flagellum followed by the formation of a pair of bends at the two ends of the straight region. The formation of a PR (principal and reverse bends in a proximo-distal sequence) or an RP bend-pair is interpreted as a result of active sliding of doublet subset (1-4) or (6-9) respectively in the interbend region. The percentage of PR responses increased with the initial local curvature of the resting R bend and the distance of the stimulated site from the flagellar base, and decreased with the age of the preparation.