抄録
The decrease in blood flow and the increase in sympathetic nerve activity to kidney are occurred during exercise. The feedforward neural drive from higher brain (central command) adjusts autonomic nervous system and evokes cardiovascular responses. We investigated whether central command increases renal sympathetic nerve activity (RSNA) and decreases renal blood flow (RBF), using mid-collicular decerebrate and unanesthetized rats (n=17). Rats were instrumented with laser flowmeter probe in a kidney (ALF21, Advance) (n=10), an electrode on renal nerves (n=7), and a catheter in carotid artery (all rats). Central command was evoked for 30 s by electrical stimulation of midbrain in paralyzed rats. The electrical stimulation was applied to the area where it evoked behavior (20–60 μA current for 1 ms, 60 Hz). The stimulation significantly increased arterial pressure (peak change from baseline at 60 μA current: +60±6 mmHg, mean±S.E.) and RSNA (+210±30%), and decreased RBF (–34±6%). Those changes were greater as current intensity of the stimulation was greater. The decrease in RBF evoked by central command was abolished after cutting renal nerves. Our findings suggest that central command decreases RBF by the increase in RSNA. [Jpn J Physiol 54 Suppl:S91 (2004)]
