Dopamine receptor subtypes in the human coronary vessels of healthy subjects.
OBJECTIVE
Dopamine D(1)-D(5) receptors subtypes were studied in human coronary vessels of healthy subjects to assess their localization and their expression.


METHODS
Samples of intraparenchymal and extraparenchymal branches of human coronary arteries and veins were harvested from four normal native hearts explanted from four young brain dead heart donors in case of orthoptic transplant, not carried out for technical reasons. In all the samples morphological, biochemical, immunochemical, and morphometrical studies were performed including quantitative analysis of images and evaluation of data.


RESULTS
Microanatomical section showed healthy coronary vessels, which expressed all dopamine receptors (from D(1) to D(5)) with a different pattern of distribution between the different layers, in the intra and in the extraparenchymal branches.D(1) and D(5) (with a prevalence D(1) over D(5)) were distributed in the adventitia and to a lesser extent in the outer media but they were absent in arterioles, capillaries and venules. Endothelial and the middle layer showed D(2), D(3) and D(4) receptors, with a greater expression of D(2). Immunoblot analysis of dopamine monoclonal antibodies and dopamine receptors showed a different migration band for each receptor: D(1) (45 KDa); D(2) (43 KDa); D(3) (42 kDa); D(4) (40-42 KDa); D(5) (38-40 KDa)


CONCLUSIONS
These findings demonstrate the presence of all dopamine receptor subtypes in the wall of human coronary vessels of healthy subjects. Dopamine D(1) and D(2) receptor subtypes are the most expressed, suggesting their prominent role in the coronary vasoactivity.
Tonnarini
Gianfranco
G
Clinical Science (Policlinico Umberto I), "Sapienza" University, Rome, Italy. gianfranco.tonnarini@uniroma1.it
Parlapiano
Claudio
C
Cavallotti
Daniela
D
Tego
Andi
A
Curione
Mario
M
Giancaspro
Giuseppe
G
Vincentelli
Giovanni Maria
GM
Leone
Silvia
S
Cavallotti
Carlo
C
D000328:Adult; D003331:Coronary Vessels / Q000166:cytology / Q000378:metabolism*; D003720:Densitometry; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D006262:Health; D006801:Humans; D015151:Immunoblotting; D011954:Receptors, Dopamine / Q000145:classification* / Q000378:metabolism*
D011954:Receptors, Dopamine