Dopamine Autoreceptors Modulate Dopamine Release from the Prefrontal Cortex |
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Authors: | Reiza K Talmaciu Irene S Hoffmann L X Cubeddu |
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Institution: | Division of Clinical Pharmacology, Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill. North Carolina, U.S.A.;School of Pharmacy, Department of Pharmacology, Central University of Venezuela, Caracas, Venezuela |
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Abstract: | Electrical stimulation (at 0.3, 1, or 10 Hz, 120 pulses each) produced a calcium-dependent overflow of radioactivity from slices of the rabbit prefrontal cortex preloaded with 3H]3,4-dihydroxyphenylethylamine (3H]DA, 3H]dopamine) in the presence of desipramine. Flat frequency-release curves were observed. Apomorphine and LY-171555 inhibited in a concentration-dependent fashion the evoked overflow of DA, an effect antagonized by haloperidol. Stimulation frequencies comparable to normal firing rates of mesocortical neurons (10 Hz) drastically reduced apomorphine-induced inhibition of DA overflow. Haloperidol produced greater facilitation of DA overflow at 10 than at 1 Hz. Nomifensine, a neuronal uptake inhibitor, enhanced DA overflow. These results indicate that mesocortical DA neurons projecting to the prefrontal cortex have release modulatory autoreceptors of the D2 subtype. |
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Keywords: | Dopamine autoreceptors Rabbit prefrontal cortex Dopamine release Desipramine Apomorphine LY-171555 Haloperidol Nomifensine Electrical stimulation |
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