Differentiation of nerve terminals in the crayfish opener muscle and its functional significance

摘要: Junctional potentials (jp's) recorded from superficial distal fibers of the crayfish opener muscle are up to 50 times larger than jp' in central when single motor axon that innervates is stimulated at a frequency 1/sec or less. At 80/sec, contrast, jp's four those observed fibers. The tension produced by either type directly proportional integral time-voltage curve minus an excitation-contraction coupling threshold 3 mv. Distal therefore produce almost all total low frequencies stimulation and add increasingly greater contribution as their nerve endings begin facilitate response increased rate discharge. Differentiation membrane characteristics (input resistance, space constant, time constant) cannot account for these differences facilitation ratios. mechanism neuronal differentiation not based upon size effectiveness transmitter quanta, since equal sized have variances;: mjp sizes variances also equal. No were found between fiber types rates mobilization, density innervation, relationship release terminal depolarization. Single terminals on with probability terminals. More effective invasion impulse can difference.