DMT self-administration by monkeys in isolation

Abstract

Three rhesus monkeys trained to smoke lettuce cigarettes for water reward extinguished responding when given water ad lib or when the hallucinogen dimethyltryptamine (DMT) was added to the lettuce. Monkeys were then individually confined to an operant unit placed in a sensory isolation chamber that deprived them of light and sound but permitted infrared video monitoring. After continuous isolation for several days. two monkeys consistently selfadministered DMT in performance marked by dramatic changes in perceptual-motor behaviors. These results suggest that animals will self-administer a hallucinogen when it provides stimulation in an otherwise deprived environment.

Effects of 2,5-Dimethoxy-4-Methylamphetamine (DOM) and 2-Piperazin-1-yl-Quinoline (Quipazine) on Fentanyl Versus Food Choice in Rhesus Monkeys

“…When available alone, neither DOM nor quipazine increased choice of drug over food. The failure of both drugs to increase drug choice is consistent with numerous reports that 5-HT 2A agonists do not reliably exhibit reinforcing or rewarding effects in nonhuman subjects, as demonstrated by failure to maintain responding under selfadministration procedures (e.g., Deneau et al, 1969;Fantegrossi et al, 2004;Maguire et al, 2013;Yanagita, 1986;see Goodwin, 2016 andSiegel andJarvik, 1980 for rare exceptions) and failure to decrease threshold under intra-cranial self-stimulation procedures (e.g., Sakloth et al, 2019). Moreover, the lack of robust rewarding effects under several preclinical procedures is consistent with assessments that 5-HT 2A agonists likely have very low or no abuse potential relative to other drugs in humans (e.g., Johnson et al, 2018;Heal et al, 2018).…”

The serotonin 5-HT2Creceptor and the non-addictive nature of classic hallucinogens

“…These findings have withstood the test of time, as the primary literature is virtually devoid of any accounts of self-administration of CH, suggesting that there are very limited conditions under which laboratory animals voluntarily consume CH. In one example, extreme environmental conditions were required to elicit self-administration of DMT in monkeys ( Siegel and Jarvik, 1980 ). In this study, under baseline conditions, monkeys sampled DMT but did not engage in significant or persistent self-administration.…”

Animal Models of Drug Self-Administration by Smoking

“…Whether this performance was induced by a rate-increasing effect of cocaine or by a reinforcing effect of the drug is not known. Siegel and Jarvik (1980) repeated these observations in a different order, finishing the experiment with nonwater-deprived cocaine smoking; this final condition provided 23-hour access to cocaine cigarettes rather than just 1 hour. Two monkeys tended to distribute puffing fairly evenly across the first few hours and then quit, only to resume after the daily l-hour break for service.…”

“…The authors interpreted these finding cautiously, indicating that a decrease in the probability of lever pressing during hashish availability may have been an effect of hashish smoke on lever pressing, rather than a true preference; taste was also a complicating factor. Siegel and Jarvik (1980), using animals with tobacco-and cocaine-puffing histories, established puffing on lettuce cigarettes by requiring a l-second puff duration for access to 1.5 ml water, the monkeys earned all of their daily water in this manner in a 1-hour session. Termination of the water deprivation eliminated puffing.…”