[Medullary mechanism of the inhibition on renal sympathetic efferent activities by stimulation of the cervical vagal afferent nerve in rabbits].

Experiments were performed on 63 rabbits anesthetized with pentobarbital, paralyzed with gallamine triethiodide and ventiled artifically. Ipsilateral renal sympathetic nerve discharge (RSND), unit discharges of rostral ventrolateral medulla (RVL), caudal ventrolateral medulla (CVL) and blood pressure (BP) were recorded. The sympatho-inhibitory response were evoked by stimulation of the central end of vagal nerve (CVN) (731/788 exp.). The inhibitory duration is 3.6 +/- 0.185 s. The responses vary with the functional state of the CNS. The RSND inhibitory duration could be shortened or prolonged, depending on the excitatory background of RSND or the basal sympathetic tonic activity. The results indicate that CVN-induced inhibitory of RSND may be mediated, at least partly, by excitation of NTS and CVL, which results, in turn, in depressing RVL and final reduction of sympathetic efferent activity.