In chronic spinal dogs, several indoleamines and phenethylamines were tested and compared to LSD and amphetamine. Psilocin, mescaline, dimethyltryptamine, and tryptamine acted like LSD. DOM, DOB, DMA, and TMA were mostly LSD-like but had some amphetamine-like effects. PMA and PEA were mainly amphetamine-like with some LSD-like activity. MMDA and MDA showed a mix of LSD and amphetamine properties plus additional unique actions, suggesting other modes of action. Antagonists like phenoxybenzamine and cyproheptadine were used to study effects, and some drugs were also tested in LSD-tolerant dogs and for appetite suppression.
MMDA, a hallucinogenic compound in humans, was compared to LSD in dogs. Single doses of MMDA partially resembled LSD, facilitating the flexor reflex and causing rapid breathing, hyperthermia, and analgesia, but MMDA caused greater pupil dilation. Only LSD consistently triggered a stepping reflex and increased heart rate. In interaction and cross-tolerance studies with LSD-tolerant dogs, MMDA's effects generally differed from LSD's, except for spinal cord facilitation. Cyproheptadine blocked most LSD effects but only MMDA's flexor reflex facilitation. Phenoxybenzamine blocked MMDA-induced pupil dilation, analgesia, and hyperthermia but not LSD's effects. Cross-tolerance to MMDA occurred only for flexor and skin twitch reflexes. MMDA's appetite-suppressing potency was 16 times less than d-amphetamine. The authors conclude MMDA has primarily amphetamine-like activity with some LSD-like actions.