Qualitative identity of cerebral neuronal membrane actions of 5HT LSD, and CPZ.

Extra- and intracellular recording of the cerebral cortical actions of close-arterially injected serotonin (5HT) and LSD in the cat shows them to be powerful synaptic inhibitors. They are specifically and differentially blocked by chlorpromazine (CPZ). The membrane parameters including spike generation, polarization, transmembrane conductance, and IPSPs show that all three produce qualitatively identical changes, which must, therefore, be presumed to act on the same receptors with block by CPZ taking place because of competitive inhibition. The relation of these neuronal membrane findings to the characteristic actions of LSD and CPZ in mental disturbance is considered in relation to a general concept of cerebral synaptic dysfunction.