HYPEREXCITABILITY OF CULTURED CENTRAL NERVOUS-SYSTEM NEURONS CAUSED BY TETANUS TOXIN

Rat central nervous system was cultured 5 to 6 weeks and then exposed 5 to 8 h to 2 × 10-8 g/ml tetanus toxin. Forty to fifty hours later intracellular recording revealed an increase of both resting membrane potential and amplitude of action potentials in poisoned neurons whereas input resistance and depolarizing threshold currents were significantly reduced. In addition a number of neurons exhibited tonic firing characteristics under the influence of tetanus toxin. These results suggest that tetanus toxin has postsynaptic effects under tissue culture conditions, which appear to shift the phasic discharge of these neurons to a more tonic response. Thus the presynaptic action demonstrated under in vivo conditions might not be the only possible origin of the clinical symptoms seen after tetanus intoxication. © 1979.