Mepivacaine alters vascular responsiveness to vasoconstrictors in aortic rings from normal and aortic-banded rats

The present study investigated the effects of mepivacaine on the response of rat aorta to vasoconstrictors in normal and aortic-banded animals. Cardiac hypertrophy was induced in Wistar rats by aortic banding, while sham-operated animals served as controls. Isolated aortic rings with or without endothelium were contracted with potassium chloride and phenylephrine in the presence of mepivacaine (10(-3) M). Maximal tension was measured at the highest concentration of potassium chloride and phenylephrine. Maximal response to potassium chloride was reduced in the presence of mepivacaine both in normal and aortic-banded rings. As regards the vascular reactivity to phenylephrine, aortic rings with intact endothelium from aortic-banded rats have shown increased response as compared to normal. After mepivacaine administration this difference between normal and aortic-banded rats was abolished. In conclusion, in a model of cardiac hypertrophy such as that of aortic-banding, increased response to alpha1-adrenergic stimulation is observed, which is blunted by mepivacaine administration.