Increased transient receptor potential canonical type 3 channels in vasculature from hypertensive rats.
We tested the hypothesis that transient receptor potential canonical type 3 (TRPC3) channels are increased in vascular smooth muscle cells and aortic tissue from spontaneously hypertensive rats (SHR) compared with normotensive Wistar Kyoto rats. Expression of TRPC3 was analyzed by immunohistochemistry and Western blotting. TRPC3 gene knockdown was performed by specific small interfering RNA and TRPC3 overexpression using the pAdEasy-1 system. Cytosolic calcium was measured using fluorescence spectrophotometry and vasoconstriction of aortic rings using a force transducer. In SHR, the expression of TRPC3 channel protein was significantly higher in aortic rings (1.48+/-0.05 versus 1.00+/-0.06; each n=6; P<0.01) and vascular smooth muscle cells (1.28+/-0.08 versus 1.00+/-0.03; each n=6; P<0.05) compared with Wistar Kyoto rats. Knockdown of TRPC3 gene expression by specific small interfering RNA significantly reduced the angiotensin II-induced calcium influx by 30+/-3% (n=6; P<0.01), whereas TRPC3 overexpression significantly increased it by 55+/-3% (n=6; P<0.01). The angiotensin II-induced calcium increase was significantly enhanced in vascular smooth muscle cells from SHR compared with Wistar Kyoto rats, even in the presence of the calcium channel blocker amlodipine. Angiotensin II significantly elevated the TRPC3 channel protein expression in vascular smooth muscle cells from SHR from 1.28+/-0.08 to 1.61+/-0.08 (each n=6; P<0.01). Angiotensin II-induced TRPC3 expression was prevented by telmisartan. Administration of telmisartan to SHR for 4 weeks significantly reduced blood pressure, angiotensin II-induced vasoconstriction, and TRPC3 channel protein expression in aortic tissue. TRPC3 expression was not significantly reduced after reduction of blood pressure in SHR using amlodipine. In conclusion, we give experimental evidence that increased TRPC3 channel protein expression in the vasculature is important for elevated blood pressure.
Liu
Daoyan
D
Center for Hypertension and Metabolic Diseases, Department of Hypertension and Endocrinology, Daping Hospital, Third Military Medical University, Chongqing Institute of Hypertension, Chongqing, PR China.
Yang
Dachun
D
He
Hongbo
H
Chen
Xiaoping
X
Cao
Tingbing
T
Feng
Xiaoli
X
Ma
Liqun
L
Luo
Zhidan
Z
Wang
Lijuan
L
Yan
Zhencheng
Z
Zhu
Zhiming
Z
Tepel
Martin
M
D017311:Amlodipine / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000378:metabolism* / Q000473:pathology; D001562:Benzimidazoles / Q000494:pharmacology; D001565:Benzoates / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects; D006973:Hypertension / Q000378:metabolism* / Q000473:pathology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D050052:TRPC Cation Channels / Q000378:metabolism*; D000077333:Telmisartan; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D000806:Angiotensin-Converting Enzyme Inhibitors; D001562:Benzimidazoles; D001565:Benzoates; D002121:Calcium Channel Blockers; D050052:TRPC Cation Channels; C104603:TRPC3 cation channel; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D017311:Amlodipine; D002118:Calcium; D000077333:Telmisartan