title: Quantal parameters of transmission at the frog neuromuscular junction.
abstract: Estimates of quantal release parameters at frog neuromuscular junctions showed that alterations in [Ca2+]o affected m (number of quanta), p (probability of quantal release) and n (stores of quanta available for release). The effect of [Ca2+]o depended upon the initial value for p. When p was low, raising [Ca2+]o increased m and p, but not n. However, when p was large, raising [Ca2+]o had no further effect on p but increased m and n. During prolonged repetitive nerve stimulation to cause a decrease in m, n was decreased and p was increased. This finding was attributed to a failure of transmitter mobilization to maintain the stores of transmitter available for release.
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000502:physiology; D008959:Models, Neurological; D009469:Neuromuscular Junction / Q000502:physiology*; D011336:Probability; D011894:Rana pipiens; D009435:Synaptic Transmission; D013572:Synaptic Vesicles / Q000502:physiology
chemical_list: D000109:Acetylcholine; D002118:Calcium