Localization of nigrostriatal dopamine receptor subtypes and adenylate cyclase
Quantitative autoradiography using (/sup 3/H)-SCH 23390, (/sup 3/H)-sulpiride and (/sup 3/H)-forskolin was used to assess the effects of single and combined neurotoxin lesions of the nigrostriatal pathway in the rat brain on dopamine (DA) receptor subtypes and adenylate cyclase (AC), respectively. Ibotenic acid (IA) lesions of the caudate-putamen (CPu) resulted in near total loss of both (/sup 3/H)-SCH 23390 and of (/sup 3/H)-forskolin binding in the ipsilateral CPu and substantia nigra reticulata (SNR). (/sup 3/H)-sulpiride binding in the CPu was only partially removed by this same lesion, and nigral (/sup 3/H)-sulpiride binding was virtually unchanged. 6-Hydroxydopamine (6-OHDA) and IA lesions of the substantia nigra compacta (SNC) did not affect (/sup 3/H)-SCH 23390 or (/sup 3/H)-forskolin binding, but largely removed (/sup 3/H)-sulpiride binding in the SNC. A 6-OHDA lesion of the nigrostriatal pathway followed by an ipsilateral IA injection of the CPu failed to further reduce (/sup 3/H)-sulpiride binding in the CPu. These results demonstrate that postsynaptic DA receptors in the CPu are of both the D1 and D2 variety; however, a portion of D2 receptors in the CPu may be presynaptic on afferent nerve terminals to this structure. D1 receptors in the SNR are presynaptic on striatonigral terminals, whereas the D2 receptors of the SNC are autoreceptors on nigral DA neurons. The existence of presynaptic D2 receptors on nigrostriatal DA-ergic terminals could not be confirmed by this study. Co-localization of D1 receptors and AC occurs in both the CPu and SNR.
- Research Organization:
- Univ. of Utah School of Medicine, Salt Lake City (USA)
- OSTI ID:
- 6838093
- Journal Information:
- Brain Res. Bull.; (United States), Vol. 20:4
- Country of Publication:
- United States
- Language:
- English
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DOPAMINE
RECEPTORS
BIOLOGICAL LOCALIZATION
AUTORADIOGRAPHY
BIOLOGICAL PATHWAYS
BRAIN
CYCLASES
NERVES
RATS
TRITIUM COMPOUNDS
AMINES
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CENTRAL NERVOUS SYSTEM
DRUGS
ENZYMES
HYDROXY COMPOUNDS
LABELLED COMPOUNDS
LYASES
MAMMALS
MEMBRANE PROTEINS
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NEUROREGULATORS
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ORGANS
PHENOLS
POLYPHENOLS
PROTEINS
RODENTS
SYMPATHOMIMETICS
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550201* - Biochemistry- Tracer Techniques