Mesolimbic alpha-, but not beta-adrenoceptors control the accumbal release of dopamine that is derived from reserpine-sensitive storage vesicles.
Mesolimbic beta-, but not alpha-adrenoceptors control the accumbal release of dopamine that is derived from alpha-methyl-para-tyrosine-sensitive pools of newly synthesized neurotransmitter. The aim of this study was to investigate which of these adrenoceptors control the accumbal release of dopamine that is derived from reserpine-sensitive pools of previously stored neurotransmitter. Rats, that were divided in low-responders and high-responders to novelty, were pretreated with 1 mg/kg of reserpine before the alpha-adrenergic-agent phentolamine or the beta-adrenergic-agent isoproterenol was locally applied into the nucleus accumbens. The original finding that phentolamine and isoproterenol increased accumbal dopamine levels in low-responders and high-responders was replicated. Reserpine reduced the phentolamine-induced increase of accumbal dopamine in both types of rat. However, phentolamine could still increase accumbal dopamine levels in reserpine-treated high-responders, but not anymore in reserpine-treated low-responders. Reserpine did not reduce the isoproterenol-induced increase of accumbal dopamine in any type of rat. This study demonstrates that mesolimbic alpha-, but not beta-adrenoceptors control the accumbal release of dopamine that is derived from reserpine-sensitive storage vesicles. In addition, these data confirm our previous finding that dopamine can still be released from storage vesicles of reserpinized high-responders, but not of reserpinized low-responders. The collected data underline our notion that alpha- and beta-adrenergic drugs may have therapeutic effects in patients suffering from diseases in which accumbal dopamine is involved.
Verheij
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MM
Radboud University Nijmegen Medical Center, Department of Cognitive Neuroscience, Division of Psychoneuropharmacology, 6525 EZ, Nijmegen, The Netherlands. M.Verheij@cns.umcn.nl
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D018663:Adrenergic Agents / Q000494:pharmacology; D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D005106:Exploratory Behavior; D005110:Extracellular Space / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology; D008032:Limbic System / Q000378:metabolism*; D008297:Male; D009714:Nucleus Accumbens / Q000378:metabolism*; D010646:Phentolamine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D012110:Reserpine / Q000494:pharmacology*
D018663:Adrenergic Agents; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D012110:Reserpine; D007545:Isoproterenol; D004298:Dopamine; D010646:Phentolamine