Effects of verapamil on synaptic transmission in mammalian sympathetic ganglia
Liu, H.Q.; Dun, N.J.
Zhongguo Yao Li Xue Bao 11(5): 415-418
1990
ISSN/ISBN: 0253-9756 PMID: 1966650 Document Number: 365131
Effects of verapmil (Ver) on the synaptic transmission of isolated superior cervical ganglia (SCG) were investigated by means of intracellular recording techniques. In the neurons of SCG of rabbits and guinea pigs, Ver (100-400 .mu.mol/L) depressed both the synaptic responses (f-EPSPs and/or evoked action potentials) elicited by orthodromic stimulation and the acetycholine (ACh) potentials induced by pressure ejection of ACh. 4-Aminopyridine (4-AP, 100 .mu.mol/L) and BaCl2 (5 mmol/L) facilitated the f-EPSPs inhibited by Ver, but had no notable effect on the ACh potentials depressed by Ver. Ver suppressed the ACh potentials enhanced by pyridostigmine (1 .mu.mol/L). The potentiating effect of soman (1 .mu.mol/L) on the ACh potentials was prevented by Ver. It is suggested that Ver can block the synaptic transmission of mammalian SCG by both the pre- and postganglionic mechanisms.