Switching to cue-directed behavior: specific for ventral striatal dopamine but not ventral pallidum/substantia innominata gaba as revealed by a swimming-test procedure in rats.
In this study it was investigated whether ventral striatal dopamine-induced changes in switching to cue-directed behavioral patterns were funnelled via the rostral areas of the ventral pallidum/substantia innominata (VP/SI) complex and, if so, whether changes in switching to cue-directed behavioral patterns could be elicited in the VP/SI complex by manipulating GABAergic activity. To this end rats were bilaterally equipped with cannulae directed at the ventral striatum and/or rostral VP/SI complex and subjected to a swimming-test procedure for 6 min. Injections of the dopamine-releasing agent d-amphetamine (10 microg/0.5 microl per side) enhanced the number of different cue-directed behavioral patterns while they had no effect upon the number of different non-cue-directed behavioral patterns in line with previous studies (Life Sci - 1989 1697). This increase was attenuated by a low dose of the GABAa agonist muscimol (1 ng/0.5 microl) into the rostral VP/SI complex. This dose of muscimol when injected alone into the rostral VP/SI complex had no effect upon the number of different cue-directed behavioral patterns. Only the lowest dose of the GABAa antagonist bicuculline (10-25 ng/0.5 microl per side) into the rostral VP/SI complex slightly, and in a non-d-amphetamine-like manner, increased the number of different cue-directed behavioral patterns while none of the doses had an effect on the number of different non-cue-directed behavioral patterns. Both injections of d-amphetamine into the ventral striatum and injections of bicuculline into the rostral VP/SI complex strongly increased motor activity in the 10-min period preceding the swimming test. We conclude from the data that switching to cue-directed behavioral patterns is sensitive to manipulations with the dopaminergic activity in the ventral striatum but not with the GABAergic activity in the VP/SI complex although the VP/SI transmits it to other brain structures. In contrast motor activity is sensitive to manipulations with both ventral striatal dopamine and rostral VP/SI complex GABA.
van den Bos
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Department of Psychoneuropharmacology, University of Nijmegen, P.O. Box 9101, NL-6500 HB Nijmegen, The Netherlands. r.vandenbos@las.vet.uu.nl
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D000818:Animals; D001479:Basal Ganglia / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology; D001640:Bicuculline / Q000494:pharmacology; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D003463:Cues; D003913:Dextroamphetamine / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004924:Escape Reaction / Q000187:drug effects; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D005917:Globus Pallidus / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009118:Muscimol / Q000494:pharmacology; D009434:Neural Pathways; D051381:Rats; D017208:Rats, Wistar; D013377:Substantia Innominata / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D013550:Swimming; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D000697:Central Nervous System Stimulants; D018755:GABA Agonists; D018756:GABA Antagonists; D009118:Muscimol; D005680:gamma-Aminobutyric Acid; D003913:Dextroamphetamine; D004298:Dopamine; D001640:Bicuculline