Tryptamine produces pharmacologic effects in man and the chronic spinal dog which are similar to those produced by
LSD,
mescaline,
psilocin, DMT, DOM and DOB. These effects include
tachycardia,
tachypnea,
mydriasis,
hyperreflexia, behavioral changes and in man,
hallucinations. Chronic spinal dogs treated chronically with
LSD became tolerant to its ability to produce
mydriasis,
tachycardia,
tachypnea and
hyperreflexia, and were cross tolerant to the ability of
tryptamine,
psilocin,
mescaline, DMT, DOM and DOB to produce these same effects. Further, it was found that the brain and spinal cord contained
tryptamine and could release it. Further
tryptamine levels were higher in the brainstem and spinal cord above the level of transection in the chronic spinal dog that in intact dogs, and the same in the spinal cord below the level of transection. These observations suggested that there were both ascending and descending tryptaminergic pathways. Supporting this hypothesis were the observations that
L-tryptophan also produced
hyperreflexia in the acute, but not the chronic, spinal dog and cat, and that
L-tryptophan hyperreflexia was antagonized by
alpha-methyldopa but not pCPA. These observations and others argue that the spinal cord and brain have tryptaminergic mechanisms which are distinct from serotoninergic mechanisms, and that
LSD-like
hallucinogens act in part through a tryptaminergic mechanism.