Inhibition of suplatast tosilate on EPSC in the single paratracheal ganglion neurons attached with presynaptic boutons

Abstract

Using single neurons of rat paratracheal ganglia (PTG) attached with presynaptic boutons, the effects of suplatast tosilate on excitatory postsynaptic currents (EPSC) were investigated with nystatin-perforated patch-clamp recording technique. We found that suplatast concentration-dependently inhibited the EPSC amplitude and its frequency in single PTG neurons attached with presynaptic boutons. EPSC frequency was higher sensitive to suplatast than EPSC amplitude. IC50 for EPSC frequency was 1.1×10-5 M, being similar to that for the effect on histamine release from mast cell and lower than that for the inhibitory effect on cytokine production. Suplatast also inhibited the EPSCs potentiated by bradykinin (BK), but it did not affect the potentiation itself by BK. Thus, suplatast inhibited the EPSC of PTG neurons attached with presynaptic boutons at both of presynaptic and postsynaptic sites.