Document Detail


Autoradiographic localization of dopamine D2-like receptors in the rat adrenal gland.
MedLine Citation:
PMID:  7795580     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The pharmacological profile and the anatomical localization of dopamine D2-like receptors were studied in sections of the rat adrenal gland using combined radioligand binding and autoradiographic techniques with [3H]-spiroperidol as a ligand. [3H]-Spiroperidol was bound to sections of the rat adrenal gland in a manner consistent with the labelling of dopamine D2-like receptor sites. The binding was time-, temperature- and concentration-dependent and of high affinity with a dissociation constant (Kd) value of 1.6 +/- 0.04 nM and a maximum density of binding sites (Bmax) of 60 +/- 3.6 fmol/mg tissue. Experiments on the pharmacological specificity of [3H]-spiroperidol binding to sections of the rat adrenal gland suggest the labelling of dopamine D3 and/or D4 receptors. The presence of dopamine D3 and D4 receptors in the rat adrenal gland was confirmed by the demonstration of a specific binding for the D3 radioligand [3H]-7-hydroxy-N,N-di-n-propyl-2-aminotetralin (DPAT) and for the D4 radioligand [3H]-clozapine. Light microscope autoradiography showed the highest accumulation of silver grains which correspond to [3H]-spiroperidol binding sites in the rat adrenal medulla. In the adrenal cortex, where density of silver grains is about 40% lower than in the medulla, the radioligand is accumulated primarily in the zona glomerulosa and to a lesser extent in the zona reticularis. These findings suggest that dopamine D2-like receptor sites in the rat adrenal gland cortex are primarily involved in the modulation of catecholamine secretion from the medulla and of aldosterone secretion from the cortex. The possible relevance of the occurrence of dopamine D3 and D4 receptor subtypes in the adrenal gland is discussed.
Authors:
F Amenta; A Ricci
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Clinical and experimental hypertension (New York, N.Y. : 1993)     Volume:  17     ISSN:  1064-1963     ISO Abbreviation:  Clin. Exp. Hypertens.     Publication Date:  1995 May 
Date Detail:
Created Date:  1995-07-28     Completed Date:  1995-07-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9305929     Medline TA:  Clin Exp Hypertens     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  669-88     Citation Subset:  IM    
Affiliation:
Sezione di Anatomia Umana, Università di Camerino, Italy.
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MeSH Terms
Descriptor/Qualifier:
Adrenal Glands / metabolism*
Animals
Autoradiography
Binding, Competitive
Dopamine Antagonists / metabolism
Male
Rats
Rats, Wistar
Receptors, Dopamine / metabolism
Receptors, Dopamine D2 / metabolism*
Receptors, Dopamine D3
Receptors, Dopamine D4
Spiperone / metabolism
Tissue Distribution
Tritium
Chemical
Reg. No./Substance:
0/Dopamine Antagonists; 0/Drd3 protein, rat; 0/Drd4 protein, rat; 0/Receptors, Dopamine; 0/Receptors, Dopamine D2; 0/Receptors, Dopamine D3; 10028-17-8/Tritium; 137750-34-6/Receptors, Dopamine D4; 749-02-0/Spiperone

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