The effects of a single exposure to uncontrollable stress on the subsequent conditioned place preference responses to oxycodone, cocaine, and ethanol in rats
- 417 Downloads
Acute stress has been shown to facilitate the rewarding effects of a number of commonly abused drugs, although the stressor typically must be administered either immediately before or during drug administration and often in the same environment. We have previously reported that a single session of an uncontrollable (inescapable tailshock, IS), but not controllable (escapable tailshock, ES), stressor can enhance the conditioned place preference (CPP) response to morphine, even when stressor and drug administration are separated temporally and spatially. However, this persistent, trans-situational enhancement did not occur to amphetamine CPP.
The following experiments were conducted to determine whether the long-term effects of IS on drug reward are specific to opioids.
Materials and methods
Adult, male Sprague–Dawley rats were exposed to a single session of IS or remained in their home cages (HC). Twenty-four hours later, using an unbiased procedure, CPP conditioning was conducted with either oxycodone (0, 2, or 5 mg/kg, sc), cocaine (0, 1, 5, or 10 mg/kg, ip), or ethanol (0.3, 1, or 2 g/kg, ip). Another group of rats were exposed to IS, ES, or HC treatment and conditioned with oxycodone (5 mg/kg, sc) 24 h later.
IS enhanced the subsequent CPP response to oxycodone, but not cocaine or ethanol. This enhancement was dependent on the controllability of the stressor, as ES did not affect oxycodone CPP.
These results indicate that the long-term, trans-situational enhancing effect of uncontrollable stress on drug reward is specific to opioids.
KeywordsReward Uncontrollable stress Oxycodone Opioid Cocaine Psychostimulant Ethanol CPP Sensitization Rat
- Bland ST, Twining C, Schmid MJ, Der-Avakian A, Watkins LR, Maier SF (2004) Stress potentiation of morphine-induced dopamine efflux in the nucleus accumbens shell is dependent upon stressor uncontrollability and is mediated by the dorsal raphe nucleus. Neuroscience 126:705–715PubMedCrossRefGoogle Scholar
- Der-Avakian A, Will MJ, Bland ST, Deak T, Nguyen KT, Schmid MJ, Spencer RL, Watkins LR, Maier SF (2005) Surgical and pharmacological suppression of glucocorticoids prevents the enhancement of morphine conditioned place preference by uncontrollable stress in rats. Psychopharmacology (Berl) 179:409–417CrossRefGoogle Scholar
- Le AD, Poulos CX, Harding S, Watchus J, Juzytsch W, Shaham Y (1999) Effects of naltrexone and fluoxetine on alcohol self-administration and reinstatement of alcohol seeking induced by priming injections of alcohol and exposure to stress. Neuropsychopharmacology 21:435–444PubMedCrossRefGoogle Scholar
- Will MJ, Der-Avakian A, Bland ST, Grahn RE, Hammack SE, Sparks PD, Pepin JL, Watkins LR, Maier SF (2004) Electrolytic lesions and pharmacological inhibition of the dorsal raphe nucleus prevent stressor potentiation of morphine conditioned place preference in rats. Psychopharmacology (Berl) 171:191–198CrossRefGoogle Scholar