The effects of acute ethanolamine administration on isoprenaline-induced myocardial infarction in adult Wistar rats

Cardiovascular stress, such as that due to the synthetic catecholamine, isoprenaline (iso), can induce myocardial infarction (MI). Ethanolamine (etn) is a biogenic amine, found in certain food types, that protects the isolated rat heart against ischemiareperfusion injury. The aim of this study was to investigate the cardioprotective effects of acute etn on iso-induced MI. Male Wistar rats (250-350 g) were divided into four groups: Control (saline injections only), iso + etn (iso 67 mg/kg, s.c. and etn 10 mg/ kg i.p.), iso (67 mg/kg, s.c. and a saline injection), and etn (saline injection and 10 mg/kg i.p.). Rats were anaesthetised with sodium pentobarbitone (60 mg/kg, i.p.) and mechanically ventilated with room air. Arterial blood pressure wasmeasured from the right carotid artery and electrocardiogram (ECG) was recorded from surface leads. Infarct size was measured using triphenyltetrazolium chloride (TTC) staining and the by-products of lipid peroxidation were quantified. Iso administration significantly increased the infarct size (62.0±3.9%, Pb0.001) (mean±SEM) compared to control rats (23.7±2.7%). The heart weight/body weight (HW/BW) ratio was also significantly raised in iso rats (4.6±0.1, Pb0.001) compared to control rats (3.4±0.02). Iso + etn (5.0±0.2 Pb0.05) treated rats displayed significantly greater HW/BW ratio compared to iso treated rats. However, there was no significant difference in infarct size between iso and iso + etn. Iso + etn treated rats had a lower death rate (1.9%) compared to iso rats (11.3%). There was a significant increase in the amount of conjugated dienes (CD) in iso rats (59.56±2.6 μmol/L) compared to control rats (39.9±4.0 μmol/L, Pb0.05). There was no significant difference in the generation of CDs between control and iso + etn rats. In summary, etn seems to protect the rat from iso-induced MI; however the possibility of increased cardiac hypertrophy needs further investigation.