[Effects of neuroendocrine obesity induction on systemic hemodynamics and left ventricular function of normotensive...

The aim of this study was to evaluate the effects of obesity induced by neonatal Monosodium Glutamate (MSG) administration upon body weight, tail blood pressure, systemic hemodynamics and left ventricular function of Wistar rats. Two groups of Wistar rats were prepared: a) 18 animals made obese through the administration of 2 mg/Kg/SC of MSG during the first 11 days of the neonatal period and b)16 control animals (vehicle treated for the same period). Adults animals were followed from the 3rd up the 6th month of life with blood pressure and body weight being measured twice a week. At the end of this period, in part of animals from both groups, we evaluated the left ventricular function through the Langendorff isolated heart preparation whereas the remainders were used to evaluate the systemic hemodynamics through a termodilution method.

MSG animals showed significant increases in heart rate (WST=235.0+/-35.1; MSG=312.0+/-90.8 bpm), total peripheral resistance (WST=0.312+/-0.100; MSG=0.535+/-0.195 mmHg.ml(-1).min) and in relative epididymal adipose tissue content (WST=2.076+/-0.622; MSG=2.731+/-0.722 g/100 g) and a reduction of systolic volume (WST=1.020+/-0.364; MSG=0.748+/-0.455 microl/bat). An increase in mean arterial pressure was also detected in obese animals during the hemodynamic evaluation. The increases in HR and TPR and the reduction in SV suggest an augmentation in the sympathetic activation of those obese normotensive rats associated with an increased visceral fat deposition.