Document Detail

The relationship between the occupation of the D-1 dopamine receptor by [3H]piflutixol and the activity of dopamine-sensitive adenylate cyclase in rat striatal membranes.
MedLine Citation:
PMID:  1650205     Owner:  NLM     Status:  MEDLINE    
The relationship between occupation of the D-1 dopamine receptor by [3H]piflutixol and inhibition of dopamine-sensitive adenylate cyclase has been studied. Experiments were performed in parallel; after the initial incubation to enable binding of [3H]piflutixol, half the tubes were assayed for [3H]piflutixol binding and the other half assayed for adenylate cyclase activity. The assay conditions for the two halves of the experiments were identical. (+/-)Sulpiride (3 x 10(-5)M) was present in all tubes to mask drug binding to the D-2 receptor. The inhibition of dopamine- (10(-3) and 10(-5)M) sensitive adenylate cyclase with increasing concentrations of [3H]piflutixol in the incubation mixture was compared to the saturation of specific [3H]piflutixol binding with those same concentrations of [3H]piflutixol. There was a linear relationship between receptor occupation by [3H]piflutixol and inhibition of dopamine sensitive adenylate cyclase. In a second experiment dopamine was present during the initial incubation with [3H]piflutixol. This resulted in a displacement of specific [3H]piflutixol binding and, as a consequence, a reduction of [3H]piflutixol's inhibition of dopamine-sensitive adenylate cyclase. In the absence of GTP in the initial incubation dopamine produced a greater reduction of [3H]piflutixol's inhibition of dopamine adenylate cyclase than displacement of specific [3H]piflutixol binding. In the presence of GTP in the initial incubation both displacement curves were shifted to the right, i.e. dopamine was less potent. However, under these conditions dopamine produced less inhibition of [3H]piflutixol's inhibition of dopamine adenylate cyclase than displacement of specific [3H]piflutixol binding. These results are interpreted as resulting from changes in D-1high and D-1low ratios as a result of incubation in the presence or absence of GTP.
S Fleminger
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biochemical pharmacology     Volume:  42     ISSN:  0006-2952     ISO Abbreviation:  Biochem. Pharmacol.     Publication Date:  1991 Jul 
Date Detail:
Created Date:  1991-08-23     Completed Date:  1991-08-23     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0101032     Medline TA:  Biochem Pharmacol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  229-37     Citation Subset:  IM    
Department of Neurology, Institute of Psychiatry, London, U.K.
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MeSH Terms
Adenylate Cyclase / antagonists & inhibitors,  metabolism*
Corpus Striatum / drug effects*,  enzymology
Cyclic AMP / analysis
Dopamine / pharmacology
Dose-Response Relationship, Drug
Enzyme Activation / drug effects
Guanosine Triphosphate / pharmacology
Membranes / drug effects
Receptors, Dopamine / drug effects*
Receptors, Dopamine D1
Thioxanthenes / pharmacology*
Reg. No./Substance:
0/Receptors, Dopamine; 0/Receptors, Dopamine D1; 0/Thioxanthenes; 54341-02-5/piflutixol; 60-92-4/Cyclic AMP; 86-01-1/Guanosine Triphosphate; EC Cyclase

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