PENTYLENETETRAZOL - AN ANTAGONIST OF GABA AT PRIMARY AFFERENTS OF ISOLATED FROG SPINAL-CORD

In the isolated frog spinal cord, pentylenetetrazole in concentrations over 10-2 M, selectively abolished dorsal root potential evoked by ventral root stimulation and attenuated dorsal root potential generated by stimulation of adjacent dorsal root. In the same concentration pentylenetetrazole differentially affected some neutral amino acid responses without interfering with the glutamate response. On the dorsal root, .beta.-alanine and taurine depolarizing responses were abolished and the .gamma.-aminobutyric acid response was attenuated. In contrast to other convulsants, pentylenetetrazole antagonized the depolarizing component of neutral amino acid responses of frog motoneurones.