EFFECTS OF METHYL-AND ETHYL-DERIVATIVESOF NH₄⁺ ON THE NEUROMUSCULAR JUNCTION

Abstract

Studies were made to know whether some of methyl-and ethyl-derivatives of NH₄⁺can replace the role of Na⁺ in the medium concerning the ACh de-polarization of the end-plate of the muscle. The sartorius muscle of frog andtoad was used and following results were obtained:
1. The size of e.p.p. in a curarized muscle decreased very much when 4/5 of the total NaCl contained in the medium was replaced by sucrose, but a full re-covery was observed when the medium was again replaced by another one whichcontained, instead of sucrose, either NH3CH3Cl, NH₃CH₂CH₃Cl, NH₃CH (CH₃) ₂Cl or NH₂ (CH₃) ₂Cl. In a non-curarized muscle, a neuromuscular block produced bya low Na medium was recovered by applying the above mentioned solution.
2. A marked ACh contracture was demonstrated in a muscle soaked formany hours in a medium whose Na⁺ was wholely replaced by either NH₃CH₃+or NH₃CH₂CH₃⁺.
3. ACh depolarization, measured by the moving fluid surface electrodemethod, was larger in a muscle soaked in NH₃CH_3- or NH₃CH₂CH₃ Ringer thanin a normal Ringer.