Abstract
The present study investigated the neurotensin (NT) receptor subtype (NTR) involved in the antagonistic neurotensin modulation of striatal dopamine D2 receptors observed in vitro and in vivo. The NT induced increase of the IC50 values of dopamine (DA) competition for [125I]iodosulpiride binding sites was counteracted by the NTR1-like antagonist SR48692 in rat striatal slices. Intrastriatal perfusion of pergolide induced in the awake rat an inhibition of striatal DA release that was antagonized by NT. This action of NT was counteracted by co-perfusion with the NTR1 like antagonist SR48692. These data indicate that there exists in the striatum at the prejunctional level an intramembrane antagonistic NT receptor/DA D2 receptor-receptor interaction where NTR1 like receptor activation reduces the DA D2 autoreceptor function.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Binding, Competitive / drug effects
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Binding, Competitive / physiology
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Dopamine / metabolism*
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Dopamine Agonists / pharmacology
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Dopamine D2 Receptor Antagonists
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Drug Interactions / physiology
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Male
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Neostriatum / cytology
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Neostriatum / drug effects
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Neostriatum / metabolism*
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Neurons / drug effects
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Neurons / metabolism*
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Neurotensin / antagonists & inhibitors
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Neurotensin / metabolism*
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Pergolide / pharmacology
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Pyrazoles
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Quinolines
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Radioligand Assay
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Rats
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Rats, Sprague-Dawley
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Receptors, Dopamine D2 / metabolism*
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Receptors, Neurotensin / antagonists & inhibitors
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Receptors, Neurotensin / metabolism*
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Sulpiride / analogs & derivatives*
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Synaptic Transmission / drug effects
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Synaptic Transmission / physiology*
Substances
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Dopamine Agonists
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Dopamine D2 Receptor Antagonists
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Pyrazoles
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Quinolines
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Receptors, Dopamine D2
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Receptors, Neurotensin
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iodosulpride
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SR 48692
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Pergolide
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Neurotensin
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Sulpiride
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Dopamine