Abstract
Metabolic syndrome is linked to increased cardiovascular mortality, which may be partially
attributed to cardiac sympatho-vagal imbalance. However, autonomic changes were not
evaluated during the metabolic syndrome development in a monosodium glutamate-induced
animal model. We evaluate temporal changes in cardiovascular autonomic modulation
in an animal model of metabolic syndrome. Eighteen neonate male spontaneously hypertensive
rats (SHR) were treated with monosodium glutamate (MetS), and compared with Wistar–Kyoto
(C) and saline-treated SHR (H). Lee index, insulin resistance and autonomic control
(spectral analysis) were evaluated at 3 (3-mo), 6 (6-mo) and 9 (9-mo) months of age
(compared by two-way ANOVA, p<0.05). Weight of visceral fat, Lee index and arterial pressure were higher in the
MetS vs. C and H groups (p<0.001) at all ages. Heart rate variability (HRV) was decreased in the MetS and H groups
at 3-mo and 9-mo vs. C. The LF component of HRV was reduced in the MetS group at 3-mo vs. C (p=0.032), and higher vs. C and H at 9-mo (p<0.001, all comparisons). H and MetS rats had a higher LF/HF index vs. C at 9-mo (p=0.001, all comparisons). The VLF component of systolic arterial pressure variability
of the MetS was higher earlier (6-mo) than that of the H group. A reduction of 70%,
98% and 54% in αLF index of H and MetS rats vs. C, was observed at 3, 6 and 9 months, respectively. Metabolic syndrome and hypertension in rats evolve with progressive
autonomic dysfunction (worst at 9 months), with specific derangements occurring very early.
Keywords
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References
- Hypertension in obese Zucker rats. Role of angiotensin II and adrenergic activity.Hypertension. 1996; 28: 1047-1054
- Correlation between ‘Lee index’ and carcass fat content in weanling and adult female rats with hypothalamic lesions.J. Endocrinol. 1968; 40: 527-528
- Parasympathetic dysfunction is associated with insulin resistance in fructose-fed female rats.Braz. J. Med. Biol. Res. 2008; 41: 804-808
- Heart rate variability and myocardial infarction: systematic literature review and metanalysis.Eur. Rev. Med. Pharmacol. Sci. 2009; 13: 299-307
- Energy balances in obese mice.Nutr. Metab. 1979; 23: 357-367
- Development of hypertension in a rat model of diet-induced obesity.Hypertension. 2000; 35: 1009-1015
- Unimpaired thermogenic response to noradrenaline in genetic (ob/ob) and hypothalamic (MSG) obese mice.Biosci. Rep. 1984; 4: 343-349
- Weight loss and the renin–angiotensin–aldosterone system.Hypertension. 2005; 45: 356-362
- Nocturnal hypertension in mice consuming a high fructose diet.Auton. Neurosci. 2006; 130: 41-50
- Frequency-dependent baroreflex modulation of blood pressure and heart rate variability in conscious mice.Am. J. Physiol. Heart Circ. Physiol. 2005; 289: H1968-H1975
- Autonomic activity assessed by heart rate spectral analysis varies with fat distribution in obese women.Obes. Res. 1996; 4: 55-63
- Links between metabolic syndrome and cardiovascular autonomic dysfunction.Exp. Diabetes Res. 2012; 2012: 615835
- Heart rate, sympathetic cardiovascular influences, and the metabolic syndrome.Prog. Cardiovasc. Dis. 2009; 52: 31-37
- Impaired coronary function in Wistar Ottawa Karlsburg W rats—a new model of the metabolic syndrome.Pflugers Arch. 2007; 454: 1011-1021
- Reflex sympathetic activation induces acute insulin resistance in the human forearm.Hypertension. 1993; 21: 618-623
- Aldosterone and metabolic syndrome: is increased aldosterone in metabolic syndrome patients an additional risk factor?.Hypertension. 2008; 51: 1252-1258
- The metabolic syndrome and total and cardiovascular disease mortality in middle-aged men.JAMA. 2002; 288: 2709-2716
- Association between the sympathetic firing pattern and anxiety level in patients with the metabolic syndrome and elevated blood pressure.J. Hypertens. 2010; 28: 543-550
- GLUT4 content decreases along with insulin resistance and high levels of inflammatory markers in rats with metabolic syndrome.Cardiovasc. Diabetol. 2012; 11: 100
- Central obesity and hypertension. Relationship between fasting serum insulin, plasma renin activity, and diastolic blood pressure in young obese subjects.Am. J. Hypertens. 1994; 7: 314-320
- Baroreceptor sensitivity is impaired in elderly subjects with metabolic syndrome and insulin resistance.J. Hypertens. 2006; 24: 143-150
- Cardiovascular neural regulation explored in the frequency domain.Circulation. 1991; 84: 482-492
- Overfeeding-induced obesity in spontaneously hypertensive rats: an animal model of the human metabolic syndrome.Ann. Nutr. Metab. 2010; 56: 127-142
- Heart rate variability explored in the frequency domain: a tool to investigate the link between heart and behavior.Neurosci. Biobehav. Rev. 2009; 33: 71-80
- Glimepiride as insulin sensitizer: increased liver and muscle responses to insulin.Diabetes Obes. Metab. 2008; 10: 596-600
- Application of prazosin is associated with an increase of insulin sensitivity in obese patients with hypertension.Diabetologia. 1988; 31: 415-420
- Impaired autonomic control of heart rate and blood pressure in obesity: role of age and of insulin-resistance.Clin. Auton. Res. 2001; 11: 79-86
- Effect of insulin and glucose infusions on sympathetic nervous system activity in normal man.Diabetes. 1981; 30: 219-225
- Cafeteria diet is a robust model of human metabolic syndrome with liver and adipose inflammation: comparison to high-fat diet.Obesity (Silver Spring). 2011; 19: 1109-1117
- Diabetes, glucose, insulin, and heart rate variability: the Atherosclerosis Risk in Communities (ARIC) study.Diabetes Care. 2005; 28: 668-674
- Ambulatory blood pressure, blood pressure variability and the prevalence of carotid artery alteration: the Ohasama study.J. Hypertens. 2007; 25: 1704-1710
- Simvastatin-induced cardiac autonomic control improvement in fructose-fed female rats.Clinics (Sao Paulo). 2011; 66: 1793-1796
- The sympathetic nervous system and obesity: role in aetiology and treatment.Obes. Rev. 2000; 1: 5-15
- Blood pressure and hormone changes associated with weight reduction in the obese.Hypertension. 1982; 4: 686-691
- Identification of blood pressure control mechanisms by power spectral analysis.Clin. Exp. Pharmacol. Physiol. 2007; 34: 362-368
- Insulin sensitivity, proinsulin and insulin as predictors of coronary heart disease. A population-based 10-year, follow-up study in 70-year old men using the euglycaemic insulin clamp.Diabetologia. 2005; 48: 862-867
Article info
Publication history
Published online: March 14, 2013
Accepted:
February 17,
2013
Received in revised form:
January 22,
2013
Received:
September 13,
2012
Identification
Copyright
© 2013 Elsevier B.V. Published by Elsevier Inc. All rights reserved.
