Dopamine D2-receptors regulate neurotensin release from nucleus accumbens and striatum as measured by in vivo microdialysis.
The present study was undertaken to examine the role of dopamine D2-receptors in the regulation of neurotensin release. Through a modification of the methods described by Maidment et al. (Neuroscience, 45 (1991) 81-93), we have developed a highly reproducible method of measuring changes in extracellular NT in the striatum and nucleus accumbens by in vivo microdialysis in awake animals. It was observed that calcium-dependent release of NT was evoked in both structures by infusing a high concentration of potassium. In addition, systemic administration of the D2 agonist quinpirole (5 mg/kg) induced a rapid increase of approximately 200% in extracellular NT levels in the lateral caudate and 30-40% in the nucleus accumbens. Conversely, treatment with the D2 antagonist eticlopride (0.5 mg/kg) reduced extracellular NT in the medial anterior caudate and nucleus accumbens 20-30%, but had no effect in the lateral anterior caudate. These data demonstrate for the first time that D2-receptors are important in the dopaminergic regulation of extrapyramidal and limbic NT release in conscious animals.
Wagstaff
J D
JD
Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, USA.
Gibb
J W
JW
Hanson
G R
GR
D000818:Animals; D002421:Caudate Nucleus / Q000187:drug effects / Q000378:metabolism; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D065127:Dopamine D2 Receptor Antagonists; D004558:Electric Stimulation; D007150:Immunohistochemistry; D008297:Male; D017551:Microdialysis; D017072:Neostriatum / Q000378:metabolism*; D009496:Neurotensin / Q000096:biosynthesis*; D009714:Nucleus Accumbens / Q000378:metabolism*; D010477:Perfusion; D011188:Potassium / Q000494:pharmacology; D019257:Quinpirole / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000819:agonists / Q000502:physiology*; D013469:Sulpiride / Q000494:pharmacology
D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D017448:Receptors, Dopamine D2; D019257:Quinpirole; D009496:Neurotensin; D013469:Sulpiride; D011188:Potassium