title: Morphological Identification of TRPC7 in Cardiomyocytes From Normal and Renovascular Hypertensive Rats.
abstract: OBJECTIVE
  We aimed to investigate the expression characteristics of transient receptor potential canonical 7 (TRPC7) in normal and hypertrophic cardiac myocytes.
  
  
  METHODS
  The 2-kidney 1-clip (2K1C) method was used to induce renovascular hypertension. Losartan, the potent inhibitor of angiotensin II (Ang II) receptor, was applied to the drinking water of 2K1C rats to inhibit Ang II-mediated responses. TRPC7 expression was examined by immunohisto/cytochemistry and Western blot analyses in normal and hypertrophic hearts. The expression level of protein kinase C (PKC), a negative regulator of TRPC7 channel in in vitro study, was also evaluated.
  
  
  RESULTS
  In normal rat ventricles, strong TRPC7 immunoreactivity was distributed in the surface sarcolemma of cardiomyocytes, and a moderate but striated TRPC7 immunoreactivity was also detected in the subcellular regions. The 2K1C operation caused significant hypertension and cardiac hypertrophy as demonstrated by respective biophysical or biochemical assays. At this stage, expression of TRPC7 was significantly downregulated at both tissue and cell levels, whereas that of PKC was upregulated. Further analysis revealed a negative correlation between TRPC7 and PKC expression patterns. Oral application of losartan ameliorated the extent of experimentally induced hypertension and cardiac hypertrophy. Simultaneously, it effectively reversed the downregulation of TRPC7 and mildly antagonized the upregulation of PKC.
  
  
  CONCLUSIONS
  Taken together, these results for the first time show that TRPC7 localizes in the surface and tubular sarcolemma of cardiomyocytes in normal adult rats and its expression significantly decreases in hypertrophied cardiomyocytes from renovascular hypertensive rats. TRPC7 may thus play a significant role in normal physiological settings in the heart.
authors.affiliation: Departments of *Human Anatomy, Histology and Embryology; and †Radiology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China; ‡Division of Graduate, The Fourth Military Medical University, Xi'an, China; and §Department of Ultrasound, Changsha Central Hospital, Changsha, China.
authors.forename: Long-Biao
authors.initials: LB
authors.lastname: Cui
authors.forename: Bo-Wei
authors.initials: BW
authors.lastname: Li
authors.forename: Chen
authors.initials: C
authors.lastname: Liang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Dong
authors.forename: Peng
authors.initials: P
authors.lastname: Chen
authors.forename: Chun-Rong
authors.initials: CR
authors.lastname: Zhao
authors.forename: Yun-Chao
authors.initials: YC
authors.lastname: Liu
authors.forename: Long-Long
authors.initials: LL
authors.lastname: Zheng
authors.forename: Si-Bo
authors.initials: SB
authors.lastname: Chen
authors.forename: Jie
authors.initials: J
authors.lastname: Xu
authors.forename: Xiao-Hang
authors.initials: XH
authors.lastname: Jin
authors.forename: Juan
authors.initials: J
authors.lastname: Shi