Office: 210-567-0143
Email: mcmahonl@uthscsa.edu
Drug dependence can have devastating consequences not only for the dependent individual, but also for family, friends, public health, and society. Developing effective therapies for drug dependence requires an understanding of the environmental, behavioral, and pharmacologic determinants responsible for drug use. Research in my laboratory integrates principles of behavior and receptor theory to identify mechanisms in the nervous system responsible for the abuse liability of sedative-hypnotics, opioids, and cannabinoids.
Cannabis use, in particular, has received considerable scrutiny. From the perspective of public health, cannabis appears to have some therapeutic value on the one hand and deleterious effects on performance and quality of life on the other. Current research emphasizes:
1) Mechanism(s) of cannabinoid action. The effects of cannabis that lead to its self-administration are hypothesized to be mediated by a common mechanism at a particular cannabinoid receptor subtype. Results of ongoing studies suggest that a single mechanism does not account for the behavioral effects of cannabinoids.
2) Dependence that results from chronic cannabinoid treatment. Learned behavior is being used to better understand the neuropharmacology of cannabis dependence, as defined by withdrawal upon discontinuation of cannabinoid treatment, and to identify medicines that might alleviate withdrawal in those seeking to achieve abstinence in the clinic.
Selected Recent Publications
McMahon, L.R., Amin, M.R. & France, C.P. (2005). SR 141716A differentially attenuates the behavioral effects of Δ9- tetrahydrocannabinol in rhesus monkeys. Behavioural Pharmacology. 16:363-372.
McMahon, L.R., & France, C.P. (2005). Combined discriminative stimulus effects of midazolam with other positive GABAA modulators and GABAA receptor agonists in rhesus monkeys. Psychopharmacology, 178:400-409.
McMahon, L.R., & France, C.P. (2005). Negative GABAA modulators attenuate the discriminative stimulus effects of benzodiazepines and the neuroactive steroid pregnanolone in rhesus monkeys. Psychopharmacology, 181:697-705.
McMahon, L.R., Sell, S.L., & France, C.P. (2004). Cocaine and other indirect-acting monoamine agonists differentially attenuate a naltrexone discriminative stimulus in morphine-treated rhesus monkeys. Journal of Pharmacology and Experimental Therapeutics, 308:111-119.
McMahon, L.R., Coop, A., France, C.P., Winger, G., & Woolverton, W.L. (2003). Evaluation of the reinforcing and discriminative stimulus effects of 1,4-butanediol and gamma-butyrolactone in rhesus monkeys. European Journal of Pharmacology, 466:113-120.
McMahon, L.R., & France, C.P. (2003). Discriminative stimulus effects of the cannabinoid antagonist, SR 141716A, in Δ9- tetrahydrocannabinol-treated rhesus monkeys. Experimental and Clinical Psychopharmacology, 11:286-293.
McMahon, L.R., Filip, M., & Cunningham, K.A. (2001). Differential regulation of the mesoaccumbens circuit by serotonin 5-hydroxytryptamine (5-HT)2A and 5-HT2C receptors. Jorunal of Neuroscience, 21:7781-7787.
