[Effects of tetrahydroberberine on peripheral vascular dopamine DA1 and DA2 receptor subtypes].
OBJECTIVE
To study the effect of tetrahydroberberine (THB) on the peripheral vascular dopamine DA1 and DA2 receptors.


METHODS
Using isolated vascular rings method.


RESULTS
THB(0.1-10 mumol.L-1) shifted the dose-response curves to the right in a nonparallel fashion and decreased the maximal response (Emax) of both the fenoldopam(FODA, a selective DA1 agonist)-induced and the propyl-butyl-dopamine(PBDA, a selective DA2 agonist)-induced vasorelaxation, showing a non-competitive antagonistic action. The pD'2 values of THB for FODA in the renal, pulmonary and mesenteric arteries were 5.29, 5.37 and 5.46, respectively, while for PBDA in the mesenteric and femoral arteries were 5.53 and 5.48, respectively. The potencies of this antagonistic action were weaker than those of SCH23390, a selective DA1 antagonist, domperidone, a selective DA2 antagonist and l-SPD, a mixed DA1/DA2 antagonist, domperidone, a selective DA2 antagonist and l-SPD, a mixed DA1/DA2 antagonist.


CONCLUSIONS
THB is a mixed peripheral DA, and DA2 receptor antagonist similar to l-SPD.
Zhang
W F
WF
Department of Physiology, Shanxi Medical University, Taiyuan 030001 Shanxi, China.
Zhi
J M
JM
Guo
W
W
Zhao
R R
RR
Jin
G Z
GZ
D000818:Animals; D001599:Berberine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D065127:Dopamine D2 Receptor Antagonists; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D011817:Rabbits; D017447:Receptors, Dopamine D1 / Q000819:agonists / Q000037:antagonists & inhibitors*; D017448:Receptors, Dopamine D2 / Q000819:agonists; D014664:Vasodilation / Q000187:drug effects*
D065127:Dopamine D2 Receptor Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D001599:Berberine; C004645:canadine