The neuronal mechanisms of sneeze.
スポンサーリンク
概要
- 論文の詳細を見る
In this study, we tried to analyse the neuronal mechanisms of sneeze. The subglottic pressure was recorded by a pressure transducer introduced into the subglottis through the mouth. EMGs were recorded by means of bipolar electrodes made from thin (50μm) stainless steel wires implanted into the diaphragm (DIA), rectus abdominis muscle (RA), threoarytenoid muscle (TA), and posterior cricoarytenoid muscle (PCA). Bulbar respiratory neurons located ventral to the nucleus ambiguus were recorded extracellulary by means of microelectrodes filled with Wood's alloy (n=60, inspiratory neuron: 38, expiratory neuron: 22).During spontaneous respiration, the subglottic pressure exhibited rhythmical increase and decrease. The increase (5cm H2O) and the decrease (3.5cm H2O) in the subglottic pressure reflected expiratory phase and inspiratory phase, respectively. The DIA muscle and the PCA muscle exhibited bursting discharges in phase with the inspiratory phase. The RA muscle and TA muscle were silent. The inspiratory and the expiratory neurons discharged at the corresponding respiratory phases with firing frequencies between 17 to 135 pulses/s, and between 13 to 83 pulses/s, respectively.Mechanical stimulation (vibration, frequency; 20Hz, amplitude; 0.5mm) to the nasal mucosa elicited a series of sneezes characterized by an abrupt increase in the subglottic pressure (pressure height 75-135cm H20, duration 130-175ms) followed by forceful, active expiration. After the sneeze, the amplitude and the period of subglottic pressure decreased and prolonged, respectively. Normal respiratory rhythm with regular changes in the subglottic pressure occurred 10 to 20s after the sneeze. About 30ms before the onset of the sneeze, the DIA activity was terminated and the RA muscle was reciprocally activated. About 30ms before the peak subglottic pressure, the TA activity was terminated and the PCA muscle was reciprocally activated. The inspiratory neuron started to discharge vigorously about 0.6s before the onset of sneeze, with the increase in the period of bursting discharge and the firing frequency. The expiratory neuron exhibited vigorously discharge during the period of the sneeze. After the sneeze, both the inspiratory and the expiratory neurons decreased their firing frequencies of the bursting discharges, and their discharge properties recovered with the same time course as that of subglottic pressure.All these results suggest an existence of a sneeze pattern generator, and a part of it is shared with respiratory neuronal mechanism.
- 一般社団法人 日本耳鼻咽喉科学会の論文