[Changes in respiration following trigeminal nerve block in decerebrate cats].

The intracranial blockade of trigeminal nerves increased the lung ventilation (VI) by 11% and decreased the duration of expiration (TE) by 19% in tracheal respiration. With trigeminal nerves intact, the transition from tracheal to nasal respiration was accompanied by decrease of the tidal volume (VT) by 17%; of the respiratory frequency by 10% and of the V by 26%. These changes seem to originate from stimulation of nasal cavity receptors by airflows. The data obtained suggest that afferent impulses in trigeminal nerves cause a decrease in sensitivity of the respiratory center to CO2 and augmentation of the TE. In quiet breathing, influences of the trigeminal impulses are weaker than those of the vagus, but stronger than in the afferents from chest wall mechanoreceptors.