A small percentage of people who experiment with addictive substances become drug addicts. Addiction is the result of the interaction among an addictive substance, a vulnerable individual and his/her environment. If we could predict which users are most likely to become addicts and learn what environmental variables are most likely to precipitate addiction, we could more successfully target prevention efforts. It is well-known that users who begin drug-taking in early adolescence are more likely to become addicts than those who wait until late adolescence or adulthood. Furthermore, it is well known that stress and the stress hormones corticosterone and corticotrophin releasing factor (CRF) promote initial drug seeking and relapse in abstinent users, and are protective against the aversive effects of drugs of abuse. We hypothesize that the developing HPA axis contributes to developmental vulnerability to drug abuse in adolescents. We have obtained preliminary data to suggest that adolescents as a group have elevated HPA axis activity compared to adults, and that those adolescents with the highest levels of this activity are the most likely to initiate drug seeking. We now propose to determine whether adolescents in general or those adolescents with the most reactive stress systems are more susceptible to the addictive effects of drugs of abuse and less susceptible to the aversive effects. We will prescreen adolescent and adult rats for their behavioral and neuroendocrine responses to stress before evaluating their behavior in tasks related to cocaine's reinforcing effects, withdrawal effects, and development of addiction-like behaviors. We will use self-administration with extended training and DSM-IV modeled tests for addiction to assess drug reinforcement and addiction. In separate experiments, we will use the light-dark task to assess whether age-of-onset and stress reactivity predict severity of withdrawal-induced anxiety. These studies will assess whether adolescence is truly a vulnerable period for development of addiction. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Scientist Development Award - Research & Training (K01)
Project #
1K01DA020729-01A1
Application #
7141632
Study Section
Human Development Research Subcommittee (NIDA)
Program Officer
Lynch, Minda
Project Start
2006-09-30
Project End
2011-06-30
Budget Start
2006-09-30
Budget End
2007-06-30
Support Year
1
Fiscal Year
2006
Total Cost
$132,862
Indirect Cost
Name
Duke University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
Foscue, Ethan P; Wood, Kathryne N; Schramm-Sapyta, Nicole L (2012) Characterization of a semi-rapid method for assessing delay discounting in rodents. Pharmacol Biochem Behav 101:187-92
Schramm-Sapyta, Nicole L; Cauley, Marty C; Stangl, Dalene K et al. (2011) Role of individual and developmental differences in voluntary cocaine intake in rats. Psychopharmacology (Berl) 215:493-504
Drescher, Caitlin; Foscue, Ethan P; Kuhn, Cynthia M et al. (2011) Individual differences in cocaine conditioned taste aversion are developmentally stable and independent of locomotor effects of cocaine. Dev Cogn Neurosci 1:600-5
Schramm-Sapyta, Nicole L; DiFeliceantonio, Alexandra G; Foscue, Ethan et al. (2010) Aversive effects of ethanol in adolescent versus adult rats: potential causes and implication for future drinking. Alcohol Clin Exp Res 34:2061-9
Walker, Q David; Schramm-Sapyta, Nicole L; Caster, Joseph M et al. (2009) Novelty-induced locomotion is positively associated with cocaine ingestion in adolescent rats; anxiety is correlated in adults. Pharmacol Biochem Behav 91:398-408
Schramm-Sapyta, Nicole L; Walker, Q David; Caster, Joseph M et al. (2009) Are adolescents more vulnerable to drug addiction than adults? Evidence from animal models. Psychopharmacology (Berl) 206:1-21
Schramm-Sapyta, Nicole L; Kingsley, Megan A; Rezvani, Amir H et al. (2008) Early ethanol consumption predicts relapse-like behavior in adolescent male rats. Alcohol Clin Exp Res 32:754-62
Schramm-Sapyta, Nicole L; Cha, Young May; Chaudhry, Saba et al. (2007) Differential anxiogenic, aversive, and locomotor effects of THC in adolescent and adult rats. Psychopharmacology (Berl) 191:867-77