ABSTRACT
On the isolated rat phrenic nerve-diaphragm preparation Sin blocked the neuromuscular transmission without affecting the excitability & conductivity of phrenic nerve. Inhibitory effect of Sin on indirect contraction of diaphragm was dose-dependent, increasing with increasing dose & was antagonized by high Ca2+ solution. When the transmission was blocked by Sin, the ACh sensitivity of the chick biventer cervicis muscle was reduced. Like succinylcholine Sin induced the contractile response of the toade rectus abdominis. Neostigmine did not antagonize, but enhanced the blocking effect of neuromuscular transmission of Sin. These results indicate that Sin has some characteristics of depolarizing muscular relaxants.
ABSTRACT
The effects of Cu2+ on superior cervical sympathetic ganglion of rabbits were studied by the sucrose-gap method. Cu2+ at cumula- tive concentration inhibited ganglion action potentials. IC50 of Cu2+ was 0.26 mmol/L. The effects of Cu2+ were antagonized by neostig-miae and L-cystein, while enhanced under 1/2[Ca2+] and reduced under 3[Ca2+] .Cu2+ inhibited ganglionic N wave and P wave,without affecting LN wave.
ABSTRACT
The effect of Sin on the transmission of the impulses through isolated rabbit superior cervical sympathetic ganglia in comparison with that of curare by the sucrose - gap method was studied.Inhibi -tory effect of Sin on the action potential was dose-dependent but no effect on the excitability and conductivity of preganglionic nerves. The ID50 of Sin and curare were 1.2 mM and 0.2 mM, respectively. The effect of Sin was reduced in high Ca2+ concentration solution, and enhanced under Ca2+ free solution. Neostigmine antagonized the effect of Sin.
ABSTRACT
The effects of Zn~(2+) on the isolated superior cervical sympathetic ganglion of rabbit were stud ied with sucrese-gap method. It was found thatZn~(2+) significantly inhibited ganglienic action poten-tial with a manner of concentration-dependence.The IC-50 value was 1. 48 mmol/L. The effects ofZn~(2+) were antagonized by neostigmine and 1-cys-tein, reduced under high concentration of Ca~(2+) andenhanced under low concentration of Ca~(2+). It wasalso found that Zn~(2+) inhibited ganglionic N wave,less affected p wave and without any effect on LNwave.