The modulation of transmitter release in motor nerve endings varies with the type of muscle fiber innervated.
Electrophysiological studies of synaptic transmission in mammalian muscles revealed substantial differences between neuromuscular synapses associated with fast versus slow-twitch motor units. Synapses of fast units exhibited much higher tetanic and post-tetanic potentiation of neurotransmitter release than those of slow units. On the other hand, the tetanic potentiation of slow units increased faster as a function of the frequency of activation than that of fast units. These differences suggest a possible specialization of neuromuscular synapses with the type of motor units they are associated with.
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D005260:Female; D009119:Muscle Contraction; D009469:Neuromuscular Junction / Q000502:physiology*; D009928:Organ Specificity; D051381:Rats; D009435:Synaptic Transmission; D013997:Time Factors
D000109:Acetylcholine