Abstract
1 The effects of bicuculline on dorsal and ventral root activity and upon the depressant effect of γ-aminobutyric acid (GABA) and glycine on ventral root responses have been studied on the isolated spinal cord of the frog.
2 In the absence of stimulation, the alkaloid induced a variety of activity of which the most notable was phasic simultaneous slow wave depolarization in the dorsal and ventral roots which could be reduced or suppressed by magnesium.
3 With low concentrations of bicuculline, the adjacent dorsal root response evoked by a single stimulus was depressed maximally before an increase in the ventral root response could be discerned.
4 The bicuculline-induced dorsal root activity (in the absence of stimulation) was still apparent at times when the evoked dorsal root response was reduced.
5 Bicuculline did not differentiate between the depressant effects of GABA and glycine on the evoked ventral root responses.
6 The excitant effects of bicuculline reported here did not appear to be attributable to specific antagonism of the postsynaptic depressant action of GABA.
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Selected References
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