THE USE OF PHOSPHOCREATINE PLUS ADP AS ENERGY-SOURCE FOR MOTILITY OF MEMBRANE-DEPRIVED TROUT SPERMATOZOA

Live trout spermatozoa initiate flagellar motility for a short period of time (30 s at 18 degrees C), during which their mean beat frequency (BF) decreases steadily from 60 to 20 Hz; motility then stops abruptl y. When demembranated, the motility of axonemes lasts much longer, up to 20 min, with high beat frequency, provided that ATP (millimolar con centration) and cAMP (micromolar) are added. In the present paper, the motility of demernbranated trout sperm was investigated in the absenc e of added ATP in various incubation conditions relative to other subs trates. Without the addition of exogenous creatine kinase, the additio n of phosphocreatine (PCr) and ADP shows the appearance of a progressi ve activation of all sperm models with BF increasing with time up to h igh values. Without the addition of cAMP, the BF increases to lower va lues but flagella propagated poorly coordinated waves for only a few m in. Similar progressive activation is also observed when only ADP is a dded (without any previous in vivo activation) and BF increases up to moderate values. In this latter case, no activation occurs without add ition of cAMP. The respective roles of creatine kinase and adenylate k inase in this process were investigated by addition of specific inhibi tors such as fluorodinitrobenzene and P-1,P-5-di(adenosine-5')pentapho sphate in the above described conditions. We conclude from these obser vations that all the elements necessary for a coupling between ADP/PCr /creatine kinase on one hand and ATP/ADP/dynein on the other appear to be present in trout spermatozoa: thus the existence of a shuttle sust aining this coupling is strongly suggested. Cell Motil. Cytoskeleton 4 1:91-106, 1998. (C) 1998 Wiley-Liss,Inc.