I am a second-year Ph.D. student in the Psychopharmacology Laboratory at American University. My primary research interests revolve around the psycho- and neuropharmacology of 9-tetrahydrocannabinol (THC), the primary psychoactive constituent of marijuana, as well as the effects of adolescent use of this drug on adult cognitive function.
As a second year doctoral candidate in the Behavior, Cognition and Neuroscience program, I am currently in the process of writing up my thesis for publication and defense. My thesis assessed the effects of the kappa-opioid receptor antagonist, norbinaltorphimine, on THC-induced conditioned taste avoidance in both adolescent and adult rats. Our lab operates around the theoretical framework that drugs of abuse have both rewarding and aversive effects and a drug’s abuse potential is mediated by an individual’s balance, or lack thereof, between these affective properties. The conditioned taste avoidance procedure is a method that our lab uses to assess the aversive effects of drugs of abuse. The aversive effects of THC have previously been shown to be mediated by activity at the kappa-opioid system in adult animals; however no research has been done to assess whether the same mechanism mediates these effects in adolescents. While adolescent rats do acquire THC-induced avoidance, it is interesting to note that they are also relatively insensitive to avoidance induced by kappa agonists leading to the theory that there might be another mechanism mediating the aversive effects of THC in this age group. While my data somewhat support this theory in that norbinaltorphimine had no effect on adolescent THC-induced conditioned taste avoidance, it also had no effect in adult animals. Possible explanations to these discrepant adult findings include species differences (mice vs rats), design differences (place vs taste conditioning) and norbinaltorphimine administration differences (single vs repeated administration). My plans for future research on this topic include investigating whether these parametric differences might explain our contradictory findings.
Flax, S.M., & Riley, A.L. (In Preparation). Effects of kappa antagonism on 9-tetrahydrocannabinol (THC)-induced conditioned place avoidance in adult Sprague-Dawley rats
Flax, S.M., Wakeford, A.G.P., Rice, K.C., & Riley, A.L. (In Preparation). Effects of the kappa antagonism on 9-tetrahydrocannabinol (THC)-induced conditioned taste avoidance in adolescent and adult Sprague-Dawley rats
Wakeford, A.G.P., Flax, S.M., Pomfrey, R.L., & Riley, A.L. (In Preparation). Adolescent pre-exposure to 9-tetrahydrocannabinol (THC) does not attenuate place or taste avoidance to THC in adulthood.
Wakeford, A.G.P., Flax, S.M., and Riley A.L. (In Preparation). Low doses of 9-tetrahydrocannabinol (THC) produces taste avoidance but not place avoidance in male and female adolescent rats.
Wetzell, B.B., Muller, M.M., Flax, S.M., King, H.E., Decicco-Skinner, K.L., & Riley, A.L. (Under Review). Effect of preexposure on methylphenidate-induced conditioned taste avoidance and related BDNF/TrkB activity in the nucleus accumbens and insular cortex of the rat. Psychopharmacology.