Brain dopamine transporter in spontaneously hypertensive rats.
The brain dopamine system plays an important role in the development of hypertension.


METHODS
The amounts of the dopamine transporter (DAT) and dopamine D1 and D2 receptors in the brain were assessed by in vitro autoradiography with the ligands [125I] beta-CIT, [125I]SCH23982 and [125I]iodospiperone, respectively. Changes in this transporter and the two receptors were evaluated in spontaneously hypertensive (SH) rats and control (Wistar-Kyoto) rats at the prehypertensive (2-wk-old, n = 5) and posthypertensive (15-wk-old, n = 5) stages.


RESULTS
The beta-CIT binding for the DAT was increased significantly in the caudate-putamen (CPu) of SH rats compared with that of Wistar-Kyoto (WKY) rats at both pre- and posthypertensive stages. In the evaluation of the lateral-to-medial CPu, the beta-CIT binding on the lateral side was significantly higher than that on the medial side in SH rats at 2 wk. The SCH23982 binding for D1 receptor was increased significantly in CPu at posthypertensive SH rats.


CONCLUSIONS
Increased DAT was found before the development of hypertension, and the increased DAT and D1 receptor were found at posthypertensive SH rats. The abnormal dopamine system contributes the development of hypertension, suggesting the possibility of diagnostic imaging for the essential hypertension.
Watanabe
Y
Y
Division of Tracer Kinetics, Osaka University Medical School, Japan.
Fujita
M
M
Ito
Y
Y
Okada
T
T
Kusuoka
H
H
Nishimura
T
T
D000818:Animals; D001345:Autoradiography; D001552:Benzazepines / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D001665:Binding Sites; D001923:Brain Chemistry; D002352:Carrier Proteins / Q000032:analysis*; D002421:Caudate Nucleus / Q000378:metabolism; D003042:Cocaine / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins; D006973:Hypertension / Q000378:metabolism*; D007089:Image Enhancement / Q000379:methods; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D011699:Putamen / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D011954:Receptors, Dopamine / Q000032:analysis*; D013134:Spiperone / Q000031:analogs & derivatives / Q000493:pharmacokinetics
C049558:8-iodo-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepine-7-ol; D001552:Benzazepines; D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D011954:Receptors, Dopamine; C493216:Slc6a3 protein, rat; C053751:2'-iodospiperone; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D013134:Spiperone; D003042:Cocaine; D004298:Dopamine