DUAL EXCITATORY INNERVATION THROUGH THE DIFFERENT GANGLIONIC ROOTS IN THE UROPOD ADDUCTOR MUSCLE OF A CRAYFISH, PROCAMBARUS-CLARKII

Dual excitatory innervation of the crayfish (Procambarus clarkii) uropod adductor muscle, adductor exopodite (ADX), through different roots of the sixth abdominal ganglion, was confirmed histologically and electrophysiologically. ADX contraction induced by the exciter in the third root (R3 exciter), showed more rapid fatigue than that by the exciter in the second root (R2 exciter), possibly owing to a more rapid depletion of the transmitter substance in the process of neuromuscular transmission. The size and position of the cell bodies of the two exciters were not necessarily similar, whereas the dendritic fields appeared to be almost overlapping.