THE MUSCLE MOTOR - SIMULTANEOUS LEVERS OR SEQUENTIAL IMPULSES

We use the step-size distance equation z = u/n developed in our two pr evious papers (z is the step-size distance, u is the actin filament re lative velocity and n is the rate of ATP splitting on a given actin fi lament), and introduce one additional concept: that the impulsive cont ractile forces developed on an actin filament should proceed sequentia lly along a given actin-myosin train. This enables us to elucidate som e unexplained and puzzling data in the literature, and to predict the surprisingly high values of ATPase in intact muscle that have recently been found experimentally. It seems that a sequential impulsive model of the actin-myosin interaction may give a better explanation of many phenomena in muscle physiology than does the current model of the act ion of simultaneous levers. (C) 1997 Elsevier Science B.V.