Psychopharmacology

, Volume 211, Issue 2, pp 175–185

Effects of chronic and intermittent cocaine treatment on dominance, aggression, and oxytocin levels in post-lactational rats

Authors

    • Department of PsychiatryUniversity of North Carolina
    • Department of PsychologyUniversity of North Carolina
    • Curriculum in NeurobiologyUniversity of North Carolina
    • School of MedicineUniversity of North Carolina
  • Matthew S. McMurray
    • Department of PsychologyUniversity of North Carolina
  • Paul W. Joyner
    • Department of SurgeryUniversity of Connecticut
  • Thomas M. Jarrett
    • School of MedicineUniversity of North Carolina
  • Sarah K. Williams
    • Curriculum in NeurobiologyUniversity of North Carolina
  • Elizabeth T. Cox
    • Curriculum in NeurobiologyUniversity of North Carolina
  • Mitchell A. Black
    • Department of Internal MedicineDuke University
  • Christopher L. Middleton
    • Department of NeurosurgeryMedical College of Georgia
  • Cheryl H. Walker
    • Department of PsychiatryUniversity of North Carolina
Original Investigation

DOI: 10.1007/s00213-010-1877-9

Cite this article as:
Johns, J.M., McMurray, M.S., Joyner, P.W. et al. Psychopharmacology (2010) 211: 175. doi:10.1007/s00213-010-1877-9

Abstract

Rationale

Little is known about mechanisms underlying female rodent aggression during the late postpartum period with no pups present. Studies of aggression, dominance, and oxytocin (OT) response in cocaine-treated females are sparse.

Objectives

This study was designed to examine dominance (drinking success) and aggression in a limited-access drinking model of water competition. Acute OT level measures were made on postpartum day (PPD) 36 in several brain regions of interest. Chronic and intermittent cocaine- and saline-treated and untreated rats 10 days post-weaning were tested (without pups) over PPDs 31–35 following cessation of cocaine treatment 10–30 days before testing.

Methods

Subjects were water-deprived overnight, and triads consisting of an untreated control (UN), a chronic continuous saline-treated (CS), and chronic continuous cocaine-treated (CC; 30 mg/kg/day throughout gestation) or a UN, an intermittent saline-treated (IS), and an intermittent cocaine-treated (IC; 30 mg/kg two consecutive days every 4 days throughout gestation until PPD 20) female were tested for aggression and drinking behavior during 5 min sessions on five consecutive days. The amygdala, medial preoptic area (MPOA), and ventral tegmental area were assayed for OT levels.

Results

CC and IC females were more aggressive than controls, but only IC females drank more often than controls. OT levels were lower in the MPOA of IC and CC females than in controls.

Conclusions

Findings demonstrate that long after cessation of treatment, CC- and IC-treated non-lactating females (no pups present) had higher rates of aggression, altered drinking behavior, and acutely lower MPOA OT levels.

Keywords

CocaineAggressionOxytocinDominanceCompetition

Copyright information

© Springer-Verlag 2010