Tolerance and sensitization to chronic escalating dose heroin following extended withdrawal in Fischer rats: possible role of mu-opioid receptors.

ABSTRACT:

Rationale/objectives

Heroin addiction is characterized by recurrent cycles of drug use, abstinence, and relapse. It is likely that neurobiological changes during chronic heroin exposure persist across withdrawal and impact behavioral responses to re-exposure. We hypothesized that, after extended withdrawal, heroin-withdrawn rats would express behavioral tolerance and/or sensitization in response to heroin re-exposure and that these responses might be associated with altered mu-opioid receptor (MOPr) activity.

Methods

Male Fischer rats were exposed chronically to escalating doses of heroin (7.5-75 mg/kg/day), experienced acute spontaneous withdrawal and extended (10-day) abstinence, and were re-exposed chronically to heroin. Homecage behaviors and locomotor activity in respon

SUBMITTER: Seip-Cammack KM 

PROVIDER: S-EPMC3494815 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature