CHARACTERISTICS OF MUSCULAR-CONTRACTION CAUSED BY MAGNETIC STIMULATION

CHARACTERISTICS of muscular contraction induced by magnetic stimulatio n were studied using isolated gastrocnemius muscles of a frog. The fig ure-eight coil position was regarded as 0 degrees when the direction o f induced current was parallel to the muscle fiber axis, and 90 degree s when the induced current was perpendicular to the muscle fiber axis. Muscular contraction readily occurred with lower outputs of magnetic stimulation at 0 degrees and 180 degrees, but it was weak at 90 degree s and 270 degrees. Magnetic stimulation did not directly induce muscul ar contraction but it acted on the synapses forming end plates to musc le cells, and muscular contraction occurred if the direction of the ed dy current was parallel to the nerve which innervated the muscle cells . (C) 1998 Lippincott Williams & Wilkins.