The effects of D-lysergic acid diethylamide tartrate (LSD-25) on the cholinesterases and monoamine oxidase in the spinal cord: a possible factor in the mechanism of hallucination

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Abstract
Histochemical localization of specific and non-specific cholinesterases and monamine oxidase was studied in the spinal cord and spinal ganglia of normal rats and those treated with LSD- 25. In an attempt to standardize the results, 3 series of experiments were carried out. Procedures for comparison were as follows: tissue from animals injected with LSD- 25 compared with tissue from uninjected littermates; sections of tissue incubated in a medium containing drug and substrate compared with sections incubated in substrate minus drug; and sections of tissue pretreated with drug and normal saline before incubation compared with sections pretreated with normal saline alone. Neurons in the spinal cord showed a strong reaction for specific cholinesterase and nearly no reaction for monamine oxidase. Neurons of the spinal ganglia showed strong reactions for both enzymes. Non-specific cholinesterase was localized only in the blood vessels. In all experimental series LSD- 25 inhibited all the enzymes studied. It has been suggested that the drug acts by inhibiting the enzyme mechanism controlling the passage of excess impulses across the synapses and by raising the levels of acetylcholine, epinephrine and adrenochrome in the blood. This inhibition may allow a greater entry of impulses into the central nervous system. These impulses may reach the cerebral cortex, upset the balance of cortical functions and produce psychic symptoms. In addition, enzyme inhibition at different levels of the nervous system may disturb the autonomic nervous system.