Monosodium glutamate neonatal treatment induces cardiovascular autonomic function changes in rodents

Abstract

OBJECTIVES:The aim of this study was to evaluate cardiovascular autonomic function in a rodent obesity model induced by monosodium glutamate injections during the first seven days of life.METHOD:The animals were assigned to control (control, n = 10) and monosodium glutamate (monosodium glutamate, n = 13) groups. Thirty-three weeks after birth, arterial and venous catheters were implanted for arterial pressure measurements, drug administration, and blood sampling. Baroreflex sensitivity was evaluated according to the tachycardic and bradycardic responses induced by sodium nitroprusside and phenylephrine infusion, respectively. Sympathetic and vagal effects were determined by administering methylatropine and propranolol.RESULTS:Body weight, Lee index, and epididymal white adipose tissue values were higher in the monosodium glutamate group in comparison to the control group. The monosodium glutamate-treated rats displayed insulin resistance, as shown by a reduced glucose/insulin index (-62.5%), an increased area under the curve of total insulin secretion during glucose overload (39.3%), and basal hyperinsulinemia. The mean arterial pressure values were higher in the monosodium glutamate rats, whereas heart rate variability (>7 times), bradycardic responses (>4 times), and vagal (∼38%) and sympathetic effects (∼36%) were reduced as compared to the control group.CONCLUSION:Our results suggest that obesity induced by neonatal monosodium glutamate treatment impairs cardiac autonomic function and most likely contributes to increased arterial pressure and insulin resistance.

Monosodium Glutamate Toxic Effects and Their Implications for Human Intake: A Review

“…The injections of MSG in the first 7 days of life leading to MSGinduced obesity resulted in the increase of mean arterial blood pressure and reduction of heart rate variability, bradycardic responses, vagal and sympathetic effects at 33 weeks compared to control rats (Konrad et al 2012). …”

Cardiovascular Changes in Animal Models of Metabolic Syndrome

“…However, they showed cardiovascular autonomic dysfunction, as shown by reduced baroreflex sensitivity and vagal and sympathetic effects when compared to their controls. We observed a reduced sympathetic effect which was not followed by changes in the basal heart rate or tachycardic responses to arterial pressure changes [58]. …”

Differences in the mechanisms that induce obesity and metabolic syndrome in experimental animal models and humans may cause treatment failure

“…We recently read the article ”Monosodium glutamate neonatal treatment induces cardiovascular autonomic function changes in rodents” by Signora Peres Konrad et al with great interest(1). These authors concluded that obesity induced by neonatal monosodium glutamate treatment impairs cardiac autonomic function and most likely contributes to increased arterial pressure and insulin resistance in rats.…”