Epidemiological studies have shown that women and men differ in their patterns of substance abuse and dependence. Sex differences in the effects of D9-tetrahydrocannabinol (THC), the primary psychoactive substituent of marijuana, have been reported in humans and in rodent models;however, the mechanisms responsible for these differences are unclear and are the focus of the proposed research.
Aims 1 and 2 will determine whether sex differences in the antinociceptive and dependence-related effects of THC, respectively, are modulated by gonadal hormones, estradiol, and progesterone in females and testosterone in males. Emphasis will be on the effects of repeated THC administration on behavior, as substance abuse, by definition, requires chronic use. Dependence-related behaviors include precipitated withdrawal (somatic and affective signs), THC discrimination (a rodent model of marijuana intoxication), and conditioned place preference/aversion (CPP/CPA), a rodent model to assess the degree to which drug effects are associated with pleasure or aversion. Sex differences in tolerance to the antinociceptive effects of THC, one of the potential therapeutic indications of cannabinoid-based medications, will also be evaluated.
Aim 3 will characterize the pharmacokinetics of THC and will identify regional alterations in central CB1 and CB2 receptor densities and functioning and endocannabinoid levels that are associated with behavioral changes. Understanding these basic mechanisms underlying sex differences in antinociceptive and dependence-related effects of cannabinoids will facilitate development of sex-specific approaches to treat marijuana dependence and to use cannabinoid-based medications therapeutically, specifically in the treatment of pain and spasticity. In addition, increasing scientific knowledge of endocrinological mechanisms that affect endocannabinoid system functioning could enhance understanding and treatment of a wide variety of disorders, in which dysregulation of the endocannabinoid system has been implicated, including substance abuse, psychiatric disorders, obesity, and various neurological disorders.
The proposed research will use integrated behavioral, neurochemical, and pharmacokinetic approaches to determine how gonadal steroid hormones modulate cannabinoid pharmacology related to D9- tetrahydrocannabinol (THC)-induced analgesia and dependence. This comprehensive approach will reveal the mechanisms underlying sex differences in cannabinoid pharmacology, ultimately leading to the development of more effective sex-specific treatments for pain and for cannabinoid dependence. Results are also likely to uncover mechanisms of hormonal modulation of the brain endocannabinoid system (endogenous ligands and receptors), a key mediator of cannabinoid behavioral effects.
|Marusich, Julie A; Lefever, Timothy W; Antonazzo, Kateland R et al. (2014) Evaluation of sex differences in cannabinoid dependence. Drug Alcohol Depend 137:20-8|
|Wiley, Jenny L; Burston, James J (2014) Sex differences in ?(9)-tetrahydrocannabinol metabolism and in vivo pharmacology following acute and repeated dosing in adolescent rats. Neurosci Lett 576:51-5|
|Wakley, Alexa A; Wiley, Jenny L; Craft, Rebecca M (2014) Sex differences in antinociceptive tolerance to delta-9-tetrahydrocannabinol in the rat. Drug Alcohol Depend 143:22-8|
|Marusich, Julie A; Wiley, Jenny L (2012) Rimonabant abolishes sensitivity to workload changes in a progressive ratio procedure. Pharmacol Biochem Behav 101:575-80|
|Wiley, Jenny L; Evans, Rhys L; Grainger, Darren B et al. (2011) Locomotor activity changes in female adolescent and adult rats during repeated treatment with a cannabinoid or club drug. Pharmacol Rep 63:1085-92|
|Wiley, Jenny L; Jones, Amanda R; Wright Jr, M Jerry (2011) Exposure to a high-fat diet decreases sensitivity to ?9-tetrahydrocannabinol-induced motor effects in female rats. Neuropharmacology 60:274-83|
|Burston, James J; Wiley, Jenny L; Craig, Abimbola A et al. (2010) Regional enhancement of cannabinoid CB₁ receptor desensitization in female adolescent rats following repeated Delta-tetrahydrocannabinol exposure. Br J Pharmacol 161:103-12|
|Wiley, Jenny L; Burston, James J (2010) Chronic Delta9-tetrahydrocannabinol during adolescence increases sensitivity to subsequent cannabinoid effects in delayed nonmatch-to-position in rats. Pharmacol Biochem Behav 94:516-23|
|Wiley, Jenny L; Evans, Rhys L (2009) To breed or not to breed? Empirical evaluation of drug effects in adolescent rats. Int J Dev Neurosci 27:9-20|
|McKinney, Diana L; Cassidy, Michael P; Collier, Lauren M et al. (2008) Dose-related differences in the regional pattern of cannabinoid receptor adaptation and in vivo tolerance development to delta9-tetrahydrocannabinol. J Pharmacol Exp Ther 324:664-73|
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