[Effects of pressor area of ventral surface of medulla oblongata on the vasotonicity of renal vessels of rats].

Electrical stimulation of the pressor area of the ventral surface of medulla oblongata (VSMp) of rat elicited an enhancement of renal sympathetic nerve activities (RSNA) and an increase of MAP, pressure of kidney (PPK), which depended on the integrity of renal sympathetic nerve (RSN). The effect of VSMp on PPK could be blocked by alpha 2-adrenoceptor antagonist yohimbine, but not by alpha 1-adrenoceptor antagonist prazosine when VSMp was stimulated. alpha 2-adrenoceptor agonist clonidine perfused renal vessels induced PPK increase similar to that due to stimulation of VSMp. The results indicate that the effect of VSMp on PPK are mediated by RSN of alpha 2 type sympathetic transmitter in the tonic control renal vascularture.