Science
November 12, 1976
Barry L. Jacobs, Michael E. Trulson, Warren C. Stern
72 citations
Cats injected with LSD display distinctive behaviors, such as limb flick and abortive grooming, that are extremely rare in normal cats but become dominant after treatment. The frequency of these behaviors depends on the LSD dose, and the effects last a long time after a single injection. Repeated LSD administration leads to tolerance. These behaviors are not caused by various control drugs but are triggered by other indole nucleus hallucinogens. Because these behavioral effects are specific, reliable, easy to score, and quantifiable, they provide an animal model for studying LSD and related hallucinogens.
Science
August 3, 1979
Michael E. Trulson, Barry L. Jacobs
44 citations
The hypothesis that hallucinogenic drugs work by suppressing the activity of serotonin-producing neurons in the raphe nuclei was tested by giving LSD to freely moving cats and monitoring both their behavior and raphe neuron activity. Results generally supported the hypothesis, but several mismatches emerged: low LSD doses caused only small decreases in raphe activity yet produced clear behavioral changes; behavioral effects lasted longer than the suppression of raphe firing; and during drug tolerance, raphe neurons remained just as responsive to LSD as they were before tolerance developed.
European Journal of Pharmacology
December 1, 1983
Michael E. Trulson, Terriann Crisp, Leslie J. Henderson
21 citations
Pretreating cats with low doses of either a serotonin antagonist (methysergide) or a dopamine antagonist (haloperidol) nearly completely blocked the characteristic behavioral effects of mescaline. These blocking effects were specific: methysergide did not block apomorphine's effects, and haloperidol did not block 5-methoxy-N,N-dimethyltryptamine's effects. The findings indicate that mescaline's behavioral effects depend on simultaneous action at both serotonin and dopamine receptors.
Developmental Psychobiology
July 1, 1984
Michael E. Trulson, Gailyn A. Howell
5 citations
In cats, the behavioral effects of LSD emerge around 21 days of age and reach adult levels by 35–40 days postpartum. Behaviors such as limb-flicking, abortive grooming, head-shakes, and investigatory responses appear at low frequency before 14 days, then increase rapidly. After an acute injection, effects last about 8 hours from their first appearance. Young kittens (21–42 days old) are resistant to developing tolerance with repeated doses. LSD can elicit behaviors like head-shakes and grooming earlier than they normally appear spontaneously, suggesting the neural and muscular systems for these behaviors develop before natural use.