Changes in post-tetanic potentiation of neuromuscular transmission in chronically stretched muscle.
1. Changes in the parameters of the magnitude of PTP of m.e.p.p. frequency were examined in rat soleus muscles chronically stretched for a variety of durations (4-28 days) by leg-lengthening operations. 2. On day 4 after the operation, the magnitude of PTP in the stretched muscles obviously increased compared to the control muscles. This indicates that Ca2+-conductance in the nerve terminals increases in the stretched muscles at day 4. 3. On day 7 after the operation, there was no significant difference between the magnitudes of PTP in the control and stretched muscles. 4. After day 14 following the operation, the magnitude of PTP in the stretched muscles was smaller than that in the control muscles. This indicates that Ca2+-conductance in the nerve terminals decreases in the stretched muscles after day 14.
D000200:Action Potentials; D000818:Animals; D001852:Bone Lengthening; D002118:Calcium / Q000378:metabolism*; D007700:Kinetics; D008839:Microelectrodes; D009045:Motor Endplate / Q000502:physiology*; D009132:Muscles / Q000502:physiology*; D009469:Neuromuscular Junction / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D002118:Calcium