Candesartan and insulin reduce renal sympathetic nerve activity in hypertensive type 1 diabetic rats.
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.
Takimoto
Chie
C
Divison of Endocrinology, Metabolism and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo,Japan. CZT17240@nifty.com
Kumagai
Hiroo
H
Osaka
Motohisa
M
Sakata
Katsufumi
K
Onami
Toshiko
T
Kamayachi
Tadashi
T
Iigaya
Kamon
K
Hayashi
Koichi
K
Saruta
Takao
T
Itoh
Hiroshi
H
D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology*; D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology*; D001713:Biphenyl Compounds; D001786:Blood Glucose / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000188:drug therapy; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000188:drug therapy*; D004359:Drug Therapy, Combination; D006339:Heart Rate / Q000187:drug effects; D006943:Hyperglycemia / Q000150:complications / Q000188:drug therapy; D006977:Hypertension, Renal / Q000150:complications / Q000188:drug therapy*; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D007668:Kidney / Q000294:innervation; D016014:Linear Models; D008297:Male; D008955:Models, Cardiovascular; D017711:Nonlinear Dynamics; D051381:Rats; D011918:Rats, Inbred SHR; D013564:Sympathetic Nervous System / Q000187:drug effects*; D013777:Tetrazoles / Q000494:pharmacology*
D047228:Angiotensin II Type 1 Receptor Blockers; D001562:Benzimidazoles; D001713:Biphenyl Compounds; D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D013777:Tetrazoles; C081643:candesartan