Selective abolition of Mayer waves in conscious endotoxemic rats

The relation between vascular sympathetic tone and the amplitude of arterial pressure (AP) Mayer waves was examined by analyzing 60-min recordings of AP and renal sympathetic nerve activity (RSNA) obtained in conscious rats before and after lipopolysaccharide administration, which results in strong sympathoexcitation. Mayer waves completely disappeared together with accompanying oscillations of RSNA. Meanwhile, the gain of the sympathetic baroreceptor reflex was increased, thus suggesting that abolition of Mayer waves resulted from the previously reported reduction of vascular reactivity to α-adrenoceptor stimulation. In conclusion, the amplitude of Mayer waves cannot be used indiscriminately as an index of vascular sympathetic tone.