Cocaine enhances the reward value of medial prefrontal cortex self-stimulation.
Intracranial self-stimulation (ICSS) of at least some brain sites is thought to be mediated by mesolimbic dopamine (DA) neurons. However other ICSS sites, especially those in the medial prefrontal cortex (MFC), have been shown to be relatively insensitive to drugs (e.g. amphetamine, neuroleptics) that alter DA synaptic transmission. In the present study, rats with ICSS electrodes implanted in both the medial forebrain bundle (MFB) and the MFC were treated once per day for 10 days with cocaine (15.0 mg kg-1). Cocaine decreased the thresholds for both MFB (-51.4%) and MFC (-23.0%) ICSS. Cocaine also increased rates of responding for MFC but not MFB ICSS. These data provide additional support for the view that the MFC contributes to the rewarding effects of cocaine.
Corbett
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Division of Basic Medical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Canada.
D000818:Animals; D003042:Cocaine / Q000494:pharmacology*; D004056:Differential Threshold; D004558:Electric Stimulation; D005625:Frontal Lobe / Q000502:physiology*; D008297:Male; D008474:Medial Forebrain Bundle / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D012201:Reward; D012653:Self Stimulation
D003042:Cocaine