5-Methoxy-N,N-dimethyltryptamine: spinal cord and brainstem mediation of excitatory effects on acoustic startle.
Psychopharmacology January 1, 1980 M Davis, D I Astrachan, P M Gendelman et al. 39 citations
The drug 5-MeODMT, which acts on serotonin receptors, increased the acoustic startle reflex in rats starting at a dose of 0.12 mg/kg, with the effect growing stronger up to the highest dose tested (8.0 mg/kg). This enhancement occurred even in rats whose brains had been disconnected from the spinal cord or when the drug was applied directly to the spinal cord, indicating the effect originates in the spinal cord. Several serotonin-blocking drugs (cinanserin, cyproheptadine, propranolol) completely blocked this excitatory effect, while others did not. The findings support a theory that serotonin receptors in the spinal cord amplify startle, while those in the forebrain dampen it.