Effect of morphine applied by intrapallidal microdialysis on the release of dopamine in the nucleus accumbens
| Autor: | Yannis Anagnostakis, Christina Spyraki |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Male
endocrine system medicine.medical_specialty Microdialysis Microinjections Dopamine Striatum Nucleus accumbens Globus Pallidus Nucleus Accumbens Rats Sprague-Dawley Ventral pallidum Internal medicine Basal ganglia medicine Animals Morphine Chemistry General Neuroscience Osmolar Concentration Homovanillic Acid Corpus Striatum Rats Endocrinology Globus pallidus nervous system 3 4-Dihydroxyphenylacetic Acid medicine.drug |
| Zdroj: | Brain Research Bulletin. 34:275-282 |
| ISSN: | 0361-9230 |
| DOI: | 10.1016/0361-9230(94)90064-7 |
| Popis: | The effect of morphine, administered intrapallidally, on extracellular concentrations of DA, DOPAC, and HVA in the nucleus accumbens and striatum was studied in the behaving rat using the in vivo microdialysis technique. Unilateral application of morphine hydrochloride was performed through microdialysis probes into the rat ventral pallidum (10 microliters of 0, 2.6, 4.0, 13.0, and 26.0 mM) or globus pallidus (10 microliters of 0 and 26.0 mM). The levels of DA, DOPAC, and HVA were measured using the HPLC with EC detection in dialysates collected from the nucleus accumbens, anteromedial, and anterolateral striatum. Samples were taken every 45 min over 3 h before and over 5 h after morphine or vehicle administration. Administration of morphine into the ventral pallidum resulted in increased DOPAC and HVA concentrations in the nucleus accumbens. Pretreatment with naloxone (1 mg/kg, SC) abolished this effect of morphine. Administration of morphine into the globus pallidus resulted in increased DA, DOPAC, and HVA concentrations in the nucleus accumbens and DA in the anteromedial striatum. The levels of DA and metabolites in anterolateral striatum remained rather unchanged following morphine administered into the ventral pallidum or the globus pallidus. The changes in DA neurotransmission into the nucleus accumbens induced by morphine application into the ventral pallidum and globus pallidus are reminiscent of a phasic and tonic release of DA respectively. The results show that intrapallidal morphine increases DA neurotransmission in nucleus accumbens and suggest that the effect of morphine is mediated by ventral pallidum/mesolimbic and globus pallidus/thalamocortical pathways, depending on the site of injection. |
| Databáze: | OpenAIRE |
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