Escalation of i.v. cocaine intake in peri-adolescent vs. adult rats selectively bred for high (HiS) vs. low (LoS) saccharin intake

Nathan A. Holtz, Marilyn E Carroll

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Rationale: Adolescence marks a period of increased vulnerability to the development of substance use disorders. High sweet preference is a genetically mediated behavioral trait that also predicts vulnerability to substances of abuse. Previous research has shown that while adolescent rats selectively bred for high (HiS) saccharin intake acquire cocaine self-administration at the same rate as adult HiS rats, adolescent rats bred for low saccharin intake (LoS) acquire cocaine self-administration faster than adult LoS rats. Objectives: This study was conducted to investigate the interaction of the addiction vulnerability factors of peri-adolescence and saccharin preference on cocaine intake using an animal model of escalation of cocaine consumption over 6-h/day sessions. Methods: Peri-adolescent and adult HiS and LoS female rats self-administered i.v. cocaine (0.4 mg/kg/inf) during short-access (2-h/day) sessions for 2 days. Next, a long-access (6-h/day) period (LgA) commenced and lasted 16 days. Following LgA, session length was returned to 2-h/day for a second short access phase. Results: LoS peri-adolescent rats escalated cocaine intake over the LgA period and consumed more drug than LoS adult rats; however, peri-adolescent and adult HiS rats consumed similar amounts of cocaine during this period. Additionally, adult HiS rats self-administered more cocaine than adult LoS rats during the LgA period, while there was no phenotypic difference between the rat lines during peri-adolescence for the LgA period. During the first short-access phase, peri-adolescent rats self-administered more cocaine than adult rats. Conclusions: These results emphasize the importance of adolescent drug abuse prevention by illustrating that phenotypic protection from addiction may not be expressed until adulthood.

Original languageEnglish (US)
Pages (from-to)243-250
Number of pages8
JournalPsychopharmacology
Volume227
Issue number2
DOIs
StatePublished - May 2013

Bibliographical note

Funding Information:
Acknowledgments We thank Justin Anker, Seth Johnson, Amy Say-kao, and Natalie Zlebnik for their technical assistance. This research was supported by NIDA/NIH grants RO1 DA003240, P20 DA024196, and K05 DA015627 (MEC).

Keywords

  • Addiction
  • Adolescence
  • Bingeing
  • Cocaine
  • Escalation
  • Extended access
  • Long access
  • Saccharin
  • Selective breeding
  • Sweet preference

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