Modification by lithium of transmitter release at the neuromuscular junction of the frog.
Complete or partial replacement of Na+ by Li+ resulted in a progressively developing increase in the amplitude and quantal content of end-plate potentials of the frog neuromuscular junction. Analysis of frequency facilitation curves and estimations of the binomial parameters of release indicate that Li+ caused an increase in the probability of transmitter release. Li+ also caused a time dependent increase in the frequency of miniature end-plate potentials. The responsiveness of the miniature end-plate potentials to Li+ was depressed by elevated Ca++ and enhanced by elevated K+. Collectively, the effects of Li+ on transmitter release can be attributed to the accumulation by the nerve terminals of Li+ resulting on an increased level of intracellular Ca++.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D005071:Evoked Potentials / Q000187:drug effects; D066298:In Vitro Techniques; D008094:Lithium / Q000494:pharmacology*; D009045:Motor Endplate / Q000187:drug effects; D009469:Neuromuscular Junction / Q000187:drug effects / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D011894:Rana pipiens; D013268:Stimulation, Chemical; D009435:Synaptic Transmission / Q000187:drug effects*; D013997:Time Factors
D018377:Neurotransmitter Agents; D008094:Lithium; D011188:Potassium; D002118:Calcium