Tubocurarine binding in undercut cerebral cortex and the effect of long-term electrical stimulation

1. (1) An in vitro technique was used to study the binding capacity of the acetylcholinesterase (AChE)-rich synaptic membrane fraction of cat cerebral cortex for dimethyl-[¹⁴C]-d-tubocurarine. Observations were made on the effect of undercutting and long-term electrical stimulation of the undercut cortex upon this binding. 2. (2) Undercutting increased the binding of dimethyl-[¹⁴C]-d-tubocurarine by 63% as compared with the contralateral control cortex. In parallel studies long-term electrical stimulation of undercut cortex appreciably reduced this expected increase. 3. (3) The binding of dimethyl-[¹⁴C]-d-tubocurarine to the membranes was more directly related to membrane protein levels than to the AChE activity associated with them. 4. (4) Supersensitivity of undercut cerebral cortex is likely the result of deafferentation resulting in synaptic disuse and in a concomitantly increasing sensitivity of a post-synaptic receptor or receptors.