[Role of renal dopamine receptor in the pathogenesis of hypertension after sodium loading].
The purpose of this study is to clarify the role of renal dopamine receptor in the pathogenesis of salt-dependent hypertension. Male Wistar rats were raised under three different conditions, control, 1% NaCl loading (NaCl) and 1% NaCl plus metoclopramide with a dose of 1.5 mg/kg daily (MC), for 2 weeks. Then, renal plasma membranes were prepared by ultracentrifugation method, and maximal binding capacity (Bmax) and dissociation constant (Kd) were determined by Scatchard analysis using 3H-spiperone. And plasma aldosterone and prolactin concentration in these three groups were measured by radioimmunoassay.


RESULTS
Systolic blood pressure measured tail-cuff method significantly elevated in MC group, but not control and NaCl group. Bmax of renal dopamine receptor was 535.9 +/- 85.0 fmol/mg protein, 594.9 +/- 159.3 fmol/mg protein, 529.1 +/- 166.1 fmol/mg protein, in control, NaCl and MC group, respectively. Kd of renal dopamine receptor in NaCl group was significantly lower than control (p less than 0.05). Renal dopamine contents of NaCl and MC group were lower than control. There was a negative correlation between renal dopamine content and Bmax of renal dopamine receptor in NaCl group (r = -0.95, p less than 0.02). In MC group, plasma aldosterone concentration was slightly higher than control and NaCl group, but there was no differences in plasma prolactin concentration among these three groups.
Shigetomi
S
S
Ueno
S
S
Kohno
H
H
Tosaki
H
H
Suenaga
K
K
Hashimoto
S
S
Fukuchi
S
S
D000450:Aldosterone / Q000097:blood; D000818:Animals; D004298:Dopamine / Q000378:metabolism; D006973:Hypertension / Q000209:etiology* / Q000378:metabolism; D007668:Kidney / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000502:physiology*; D012964:Sodium / Q000008:administration & dosage / Q000494:pharmacology*
D011954:Receptors, Dopamine; D000450:Aldosterone; D012964:Sodium; D004298:Dopamine