The action of LSD on the isolated frog spinal cord: electrophysiological and ultrastructural data

In the isolated hemisected frog spinal cord, LSD induced a substantial enhancement of spontaneous dorsal and ventral root activity and a general decrease of both orthodromic and antidromic root potentials. 2. These electrophysiological modifications were reversible. The LSD homologue compound--Lisuride--was without effect. 3. Electron microscopy of the LSD-treated spinal cord revealed synaptic "omega" figures and terminals almost depleted of vesicles. 4. The results suggest that LSD acts at the synaptic level favouring the spontaneous release of transmitters from those involved in the pathways tested.