PERTUSSIS TOXIN PREVENTS NEOMYCIN-INDUCED CALCIUM-DEPENDENT ELECTROPHYSIOLOGICAL EFFECTS IN RAT HIPPOCAMPAL SLICES

1. The influence of pertussis toxin has been studied on the effects of neomycin on CA1 field potentials in rat hippocampal slices in order to determine a role played by G protein in the modulation of synaptic transmission by the drug. 2. Neomycin (500 mu M), within 30 min significantly (P < 0.01) decreased the magnitude of the somatic CA1 excitatory postsynaptic potentials (EPSP) and population spike (PS) in control hippocampal slices. 3. Neomycin (500 mu M), within 30 min failed to significantly affect the magnitude of the somatic CA1 EPSP and PS in slices obtained from animals treated intracerebroventricularly (ICV) with 1-2 mu g of pertussis toxin 3 days before. 4. The results demonstrated that pertussis toxin prevents some electrophysiological effects of neomycin, suggesting a role of G protein in the modulation of the aminoglycoside antibiotic on central synaptic transmission.