Mechanistic study of β-tubulin and its interaction with the dopamine D5 receptor, cholecystokinin B receptor, and water-sodium metabolism / 中国比较医学杂志

Objective To examine the role of β-tubulin on the interaction between the cholecystokinin B receptor (CCKBR),dopamine D5 receptor(D5R), and water-sodium metabolism. Methods Normotensive and hypertensive renal proximal tubular cells(RPTC)were equally randomized into three separate groups: a gastrin group, fenoldopam group,and gastrin+nocodazole group. Immunofluorescence was used to determine localization of β-tubulin,CCKBR,and D5R. Western blotting was used to detect CCKBR, D5R, and Na-K-ATP expression. Results Gastrin stimulation in normotensive RPTC increased D5R expression(P < 0.05)and decreased Na-K-ATP expression(P < 0.05). These changes were blocked by a tubulin inhibitor(P < 0.05). However, interaction between CCKBR, D5R, and Na-K-ATP expression was not significantly affected in hypertensive RPTC. Immunofluorescence showed that CCKBR and D5R can induce one another,followed by transport to the plasma membrane, which can prevented by a tubulin inhibitor. Further, tubulin is disordered in hypertensive RPTC,which cannot support intracellular CCKBR and D5R transport. Conclusions tubulin plays a key role in the interaction between CCKBR, D5R, and water-sodium metabolism by improving protein transfer from the cytoplasm to cell membrane.

The regulation of dilated cardiomyopathy by dopamine D5 receptor through inhibiting oxidative stress / 中国比较医学杂志

Objective To determine whether dopamine D5 receptor (D5R) regulates the development of dilated cardiomyopathy (DCM) by inhibiting oxidative stress.Methods We developed heart-specific hD5 mutant (α-MHC-hD5F173L) and wild type (α-MHC-hD5WT) transgenic mice.The NOX2 expression and ROS production were tested in the transgenic mice at three month of age.The α-MHC-hD5F173L mice were treated with either NADPH oxidase inhibitor Apocynin (1mmol/kg/day) or phosphate-buffered saline (PBS) as control by intraperitoneal injection for 4 weeks.After then, the indexes of heart function were measured.The hD5WT and hD5F173L were transfected respectively in rat H9C2 cells, in which ROS production and NOX2 expression were detected at basal level.Results The ROS production and NOX2 expression were higher in the heart of α-MHC-hD5F173L than α-MHC-hD5WT mice.Apocynin treatment improved the heart function of α-MHC-hD5F173L mice.NOX2 expression and ROS production were higher in hD5F173L than hD5WT transfected H9C2 cells.Conclusions Dopomine D5 receptor may prevent DCM development by inhibiting oxidative stress.