Candesartan and insulin reduce renal sympathetic nerve activity in hypertensive type 1 diabetic rats

Chie Takimoto, Hiroo Kumagai, Motohisa Osaka, Katsufumi Sakata, Toshiko Onami, Tadashi Kamayachi, Kamon Iigaya, Koichi Hayashi, Takao Saruta, Hiroshi Itoh

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8 Citations (Scopus)

Abstract

The nonlinearity of cardiovascular regulation is higher in normal physiology, whereas several diseases are characterized by a reduction in this nonlinearity. Reduced nonlinearity of heart rate regulation is a robust risk factor for high mortality in patients with myocardial infarction. We investigated the changes in linear and nonlinear correlations of cardiovascular regulation after administering drugs in hypertensive diabetic rats. Type 1 diabetes was induced in rats by intraperitoneally injecting spontaneously hypertensive rats with streptozotocin. The animals were then divided into 4 groups and each group was given vehicle, candesartan, amlodipine, or insulin for 2 weeks. Blood pressure, heart rate, renal sympathetic nerve activity, and renal blood flow were simultaneously recorded in the conscious state, and the linear and nonlinear correlations were compared by using coherence and the mutual information method. Candesartan and amlodipine decreased blood pressure to a similar extent, but renal sympathetic nerve activity was significantly lower in the candesartan group than in the vehicle group. The renal sympathetic nerve activity in the insulin group was also lower than in the vehicle group. There were no significant differences in linear correlation among the 4 groups. In contrast, the nonlinear correlations between renal sympathetic nerve activity and blood pressure in the candesartan group and the insulin group were significantly higher than in the vehicle group. Candesartan and insulin decreased renal sympathetic nerve activity and increased the nonlinearity. These results suggest that reducing the activity of renin-angiotensin system and insulin that lowers blood glucose level may improve autonomic nervous system dysfunction and neurohumoral regulation of the cardiovascular system in diabetic hypertensive rats.

Original languageEnglish
Pages (from-to)1941-1951
Number of pages11
JournalHypertension Research
Volume31
Issue number10
DOIs
Publication statusPublished - 2008 Dec 1
Externally publishedYes

ASJC Scopus subject areas

  • Internal Medicine
  • Physiology
  • Cardiology and Cardiovascular Medicine

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    Takimoto, C., Kumagai, H., Osaka, M., Sakata, K., Onami, T., Kamayachi, T., Iigaya, K., Hayashi, K., Saruta, T., & Itoh, H. (2008). Candesartan and insulin reduce renal sympathetic nerve activity in hypertensive type 1 diabetic rats. Hypertension Research, 31(10), 1941-1951. https://doi.org/10.1291/hypres.31.1941