Autonomic neuropathy precedes cardiovascular dysfunction in rats with diabetes.
Eur J Clin Invest
; 38(9): 607-14, 2008 Sep.
Article
em En
| MEDLINE
| ID: mdl-18837735
ABSTRACT
BACKGROUND:
Our team previously demonstrated arterial stiffening and cardiac hypertrophy in type 2 diabetic rats at 8 but not 4 weeks after being administered streptozotocin (STZ) and nicotinamide (NA). The present study focused on investigating the effects of type 2 diabetes on cardiac autonomic nerve function in the STZ- and NA-treated animals, using modern spectral estimation technique.DESIGN:
An autoregressive process was performed to each detrended signal of heart rate and systolic blood pressure measured in the 4- and 8-week STZ-NA rats with anaesthesia. The power of low-frequency and high-frequency oscillations was automatically quantified with each spectral peak by computing the residuals. The closed-loop baroreflex gain was estimated using the square root of the ratio between heart rate and systolic blood pressure powers in the low-frequency band.RESULTS:
Compared with the age-matched controls, both the 4- and 8-week STZ-NA diabetic rats had significantly decreased low-frequency oscillations of heart rate but not systolic blood pressure variability, showing a decline in baroreflex gain (0.451 +/- 0.060 and 0.484 +/- 0.056 vs. 1.196 +/- 0.064 ms mmHg(-1), P < 0.05). On the other hand, the low frequency-high frequency power ratio of the heart period was also diminished in the two diabetic groups, indicating a shift in sympatho-vagal balance of the heart control (0.472 +/- 0.109 and 0.504 +/- 0.090 vs. 1.857 +/- 0.336, P < 0.05).CONCLUSIONS:
The cardiac autonomic dysfunction in the absence of any significant changes in vascular dynamics, 4 but not 8 weeks after induction of type 2 diabetes, suggests that the diabetic autonomic neuropathy may precede arterial stiffening and cardiac hypertrophy in the STZ- and NA-treated rats.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sistema Nervoso Autônomo
/
Pressão Sanguínea
/
Cardiomegalia
/
Diabetes Mellitus Tipo 2
/
Angiopatias Diabéticas
/
Frequência Cardíaca
Tipo de estudo:
Etiology_studies
Limite:
Animals
Idioma:
En
Revista:
Eur J Clin Invest
Ano de publicação:
2008
Tipo de documento:
Article