The present study was designed to investigate the influence of long-term consumption of cola beverage on expression of cardiac atrial natriuretic peptide (ANP) gene. Natriuretic peptides, aside from their classic hemodynamic effects, have been associated with regulation of numerous physiological functions controlling energy metabolism. In rat, the effects of the consumption of cola beverage on cardiac ANP expression have not been described yet.Design and method:
Male Wistar rats received a standard diet. Additionally, a group of rats received a commercially available cola beverage to induce experimental metabolic syndrome conditions (MetS, n = 12) while controls (CON, n = 7) received standard drinking water. We measured weight gain weekly. After six months of administration, blood glucose was determined by conventional oral glucose tolerance test (oGTT). In addition, heart rate (HR), systolic and diastolic blood pressures (sBP and dBP) were measured by using tail-cuff method. Cardiac gene expression was determined by quantitative real-time polymerase chain reaction (RT-PCR) in left ventricles.Results:
We observed a significantly increased body weight in MetS rats (541 ± 12 g; P < 0.01) when compared to controls (443 ± 23 g). This was accompanied with significantly increased HR (CC: 383 ± 9 mmHg vs. CON: 312 ± 15 mmHg; P < 0.01), significantly increased sBP (MetS: 135 ± 3 mmHg vs. CON: 120 ± 4 mmHg; P < 0.01) but unaltered dBP (MetS: 86 ± 1 mmHg vs. CON: 85 ± 1 mmHg; NS). Postprandial glycaemia was significantly increased after 60 minutes (MetS: 9.3 ± 0.5 mmol/L vs. CON: 6.6 ± 0.6 mmol/L; P < 0.01) as well as after 90 minutes following oGTT induction (MetS: 8.3 ± 0.4 mmol/L vs. CON: 6.6 ± 0.5 mmol/L; P < 0.01). Left ventricles from MetS rats exhibited significant upregulation of ANP (MetS: 244 ± 0.5 % vs. CON: 100 ± 0.2 %; P < 0.01).Conclusions:
Experimental metabolic syndrome induced by cola beverage administration is characterised by increased sBP and impaired glucose utilisation and is accompanied by upregulation of cardiac expression of ANP. The data indicate that the altered expression profile in the heart could contribute to the increased incidence of hypertension, cardiovascular and also metabolic alterations observed in this animal model.