title: Social interaction reward decreases p38 activation in the nucleus accumbens shell of rats.
abstract: We have previously shown that animals acquired robust conditioned place preference (CPP) to either social interaction alone or cocaine alone. Recently it has been reported that drugs of abuse abnormally activated p38, a member of mitogen-activated protein kinase family, in the nucleus accumbens. In this study, we aimed to investigate the expression of the activated form of p38 (pp38) in the nucleus accumbens shell and core of rats expressing either cocaine CPP or social interaction CPP 1 h, 2 h and 24 h after the CPP test. We hypothesized that cocaine CPP will increase pp38 in the nucleus accumbens shell/core as compared to social interaction CPP. Surprisingly, we found that 24 h after social interaction CPP, pp38 neuronal levels were decreased in the nucleus accumbens shell to the level of naïve rats. Control saline rats that received saline in both compartments of the CPP apparatus and cocaine CPP rats showed similar enhanced p38 activation as compared to naïve and social interaction CPP rats. We also found that the percentage of neurons expressing dopaminergic receptor D2R and pp38 was also decreased in the shell of the nucleus accumbens of social interaction CPP rats as compared to controls. Given the emerging role of p38 in stress/anxiety behaviors, these results suggest that (1) social interaction reward has anti-stress effects; (2) cocaine conditioning per se does not affect p38 activation and that (3) marginal stress is sufficient to induce p38 activation in the shell of the nucleus accumbens.
authors: Experimental Psychiatry Unit, Medical University of Innsbruck, Innsbruck, Austria.
authors: Ahmad
authors: A
authors: Salti
authors: Experimental Psychiatry Unit, Medical University of Innsbruck, Innsbruck, Austria; Division of Physiology, Medical University of Innsbruck, Innsbruck, Austria.
authors: Kai K
authors: KK
authors: Kummer
authors: Experimental Psychiatry Unit, Medical University of Innsbruck, Innsbruck, Austria.
authors: Chinmaya
authors: C
authors: Sadangi
authors: Institute for Neuroscience, Medical University of Innsbruck, Innsbruck, Austria.
authors: Georg
authors: G
authors: Dechant
authors: Experimental Psychiatry Unit, Medical University of Innsbruck, Innsbruck, Austria.
authors: Alois
authors: A
authors: Saria
authors: Experimental Psychiatry Unit, Medical University of Innsbruck, Innsbruck, Austria. Electronic address: ranarawas@hotmail.com.
authors: Rana
authors: R
authors: El Rawas
mesh_terms: D000818:Animals; D003042:Cocaine / Q000494:pharmacology*; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D005455:Fluorescent Antibody Technique; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000201:enzymology; D009714:Nucleus Accumbens / Q000187:drug effects / Q000201:enzymology*; D011581:Psychological Tests; D011897:Random Allocation; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D012201:Reward; D012919:Social Behavior; D013037:Spatial Behavior / Q000187:drug effects / Q000502:physiology; D013315:Stress, Psychological / Q000201:enzymology; D013997:Time Factors; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: C000607792:DRD2 protein, rat; D018765:Dopamine Uptake Inhibitors; D017448:Receptors, Dopamine D2; D048051:p38 Mitogen-Activated Protein Kinases; D003042:Cocaine
keywords: Conditioned place preference; Drugs of abuse; Reward; Social interaction; Stress; p38 MAP kinase