Cardiorespiratory responses to stimulation of the nucleus reticularis gigantocellularis

The nucleus reticularis gigantocellularis (NGC) has been shown to be involved in somatosensory and somatomotor functions. The purpose of the present study was to determine, in anesthetized cats, the modulatory influence of the portion of the NGC at the ponto-medullary border on respiratory and cardiovascular control. Electrical stimulation (25-100 microA 70 Hz, and 1.0-msec pulse duration) significantly depressed mean arterial pressure, heart rate, breathing frequency, tidal volume and phrenic amplitude. Chemical stimulation of NGC cell bodies (1.0 M L-glutamate or 10(-3) M kainic acid) elicited similar decreases in ventilation, arterial pressure and heart rate. These results show that selective activation of cell bodies in the ponto-medullary NGC can depress, in parallel, respiratory and cardiovascular activity and suggests that the influence of diverse sensory information within this region of the reticular formation must be inhibitory to respiratory and cardiovascular output.