Psychopharmacology

, Volume 196, Issue 3, pp 473–482

CRF1 receptor antagonists attenuate escalated cocaine self-administration in rats

Authors

  • Sheila E. Specio
    • Committee on the Neurobiology of Addictive Disorders, SP30-2400The Scripps Research Institute
    • Committee on the Neurobiology of Addictive Disorders, SP30-2400The Scripps Research Institute
  • Laura E. O’Dell
    • Department of PsychologyThe University of Texas at El Paso
  • Benjamin Boutrel
    • Center for Psychiatric Neuroscience, Department of PsychiatryUniversity of Lausanne
  • Eric P. Zorrilla
    • Committee on the Neurobiology of Addictive Disorders, SP30-2400The Scripps Research Institute
  • George F. Koob
    • Committee on the Neurobiology of Addictive Disorders, SP30-2400The Scripps Research Institute
Original Investigation

DOI: 10.1007/s00213-007-0983-9

Cite this article as:
Specio, S.E., Wee, S., O’Dell, L.E. et al. Psychopharmacology (2008) 196: 473. doi:10.1007/s00213-007-0983-9

Abstract

Rationale

Previous work suggests a role for stress-related corticotropin-releasing factor (CRF) systems in cocaine dependence. However, the involvement of activation of CRF1 receptors in rats self-administering cocaine with extended access is unknown.

Objective

The current study examined whether CRF1 receptor antagonist administration alters cocaine self-administration in animals given extended access.

Materials and methods

Wistar rats (n = 32) acquired cocaine self-administration (0.66 mg/kg per infusion) in 1 h sessions for up to 11 days. Rats then were assigned to receive either daily short (1 h, ShA) or long (6 h, LgA) access to cocaine self-administration (n = 7–9 per group). Following escalation of intake, animals received one of two selective CRF1 antagonists: antalarmin (6.3–25 mg/kg, i.p.) or N,N-bis(2-methoxyethyl)-3-(4-methoxy-2-methylphenyl)-2,5-dimethyl-pyrazolo[1,5a]pyrimidin-7-amine (MPZP; 3.6–27.5 mg/kg, s.c.).

Results

By day 11 of the escalation period, LgA rats increased their cocaine intake, reaching an intake level of 15.1 mg/kg, compared to 11.1 mg/kg in ShA rats, during the first hour of sessions. Antalarmin reduced cocaine self-administration at the highest dose selectively in the LgA group but not the ShA group. MPZP reduced cocaine intake both in LgA and ShA rats. However, MPZP did so at a lower dose in LgA rats than in ShA rats. Within the LgA group, MPZP decreased cocaine intake in the first 10 min (loading phase) as well as in the latter session intake (maintenance phase).

Conclusion

The data suggest that hypersensitivity of the CRF system occurs with extended access to cocaine self-administration and that this altered CRF system may contribute to the increased motivation to self-administer cocaine that develops during psychostimulant dependence.

Keywords

CocaineSelf-administrationEscalationRatsCorticotropin-releasing factorAddictionAntalarminMPZP

Copyright information

© Springer-Verlag 2007