抄録
Respiratory motor outputs are involuntary rhythmic activities and also can be voluntarily controlled. In this study, we aimed to analyze the cerebral input organization to respiratory neuron network in cats and rats. For this, we examined the effects of electrical stimulation of cerebrofugal fibers on respiratory neuron activities of ventral respiratory group neurons (VRGs) in the caudal medulla, upper cervical inspiratory neurons (UCINs) of C1-2 spinal segments and phrenic motoneurons (Phr. MNs). Experiments were performed under pentobarbital (cats) or ketamine-xylazine (rats) anesthesia. Animals were immobilized with gallamine triethiodide and artificially ventilated. Bipolar simulation electrodes were localized at the cerebral peduncle (CP) and sensorimotor cortex on the right side. Single or double pulse stimulation of the CP induced short latency facilitation (4-6 ms) and succeeding suppression on respiratory activities of the phrenic nerve and UCINs on the left side, while stimulation of CP predominantly suppressed the right side inspiratory and expiratory VRG activities both in cats and rats. The present results suggest that cerebral excitatory inputs to Phr. MNs and UCINs are not transmitted through VRGs, but rather directly to Phr. MNs and UCINs. [Jpn J Physiol 54 Suppl:S54 (2004)]
