INVESTIGADORES
MALCHIODI Emilio Luis
artículos
Título:
Distribution of D4 dopamine receptor in rat brain with sequence-specific
Autor/es:
DEFAGOT MC, MALCHIODI EL, VILLAR MJ, ANTONELLI MC.
Revista:
MOLECULAR BRAIN RESEARCH
Referencias:
Año: 1997 vol. 45 p. 1 - 12
ISSN:
0169-328X
Resumen:
The distribution of the dopaminergic D4 receptor in rat brain was studiedemploying site directed polyclonal antibodies. Antisera were raised in rabbits totwo oligopeptides corresponding to amino acids 160-172 of the secondextracellular loop (P1) and amino acids 260-273 of the third intracellular loop(P2) of the D4 receptor sequence. Affinity-purified antibodies (anti-P1 andanti-P2) specifically recognized two major bands of 42-45 and 95 kDa in Westernblots of denatured preparations of various rat brain areas. Immunocyto-chemistry studies showed that D4 receptor is widely distributed in rat central nervoussystem (CNS) showing higher labelling in the hippocampus (CA1, CA2, CA3 anddentate gyrus) frontal cortex, entorhinal cortex, caudate putamen, nucleusaccumbens, olfactory tubercle, cerebellum, supraoptic nucleus and sustancia nigrapars compacta. In addition, anti-P1 decreased the binding of the antagonist[3H]YM-09151-2 selective for D2, D3 and D4 receptors but did not modify thebinding of [3H]raclopride an antagonist selective for D2 and D3, in striatalsynaptosomes. Anti-P2 did not modify the binding of these ligands. These results confirm the selectivity of the antibodies towards the D4 receptor and suggestthat the binding site for the antagonists might be located at or close to thesecond extracellular loop of the protein sequence. D4 receptor protein is mainly expressed in plasma membranes and in the peripheral cytoplasm of neurons and ismore widely distributed than was originally proposed based on mRNA localization, since it is present both in limbic, diencephalic and motor areas of rat brain.