The effect of bicuculline and baclofen on the dorsal root-ventral root reflex in the isolated spinal cord.

1. In the lumbar spinal cord, 10(-6) M bicuculline reduces the inhibition of the dorsal root-ventral root (DR-VR) reflex produced by lateral stimulation of the spinal cord. The inhibition returns on washing in control artificial cerebrospinal fluid (ACSF). 2. Baclofen (10(-6) M) inhibits the monosynaptic DR-VR reflex which returns on washing in control ACSF. 3. This suggests an involvement of GABAA receptors in the lateral inhibition and GABAB receptors in the DR-VR reflex system. 4. The increased activity seen following bicuculline or tubocurarine probably resets the "set point" of neural activity to a lower level.