Mutolo Donatella, Bongianni Fulvia, Cinelli Elenia, Fontana Giovanni A, Pantaleo Tito
Dipartimento di Scienze Fisiologiche, Unità Funzionale di Medicina Respiratoria, Università degli Studi di Firenze, Viale G.B. Morgagni 63, 50134 Firenze, Italy.
Neurosci Lett. 2008 Dec 26;448(2):200-3. doi: 10.1016/j.neulet.2008.10.057. Epub 2008 Nov 1.
We investigated the changes induced by pulmonary C-fibre receptor activation in the cough reflex evoked by mechanical stimulation of the tracheobronchial tree in pentobarbitone anesthetized, spontaneously breathing rabbits. Phrenic nerve and abdominal muscle activities were monitored along with tracheal and arterial blood pressures. The activation of pulmonary C-fibre receptors by means of right atrial injection of phenylbiguanide (PBG) caused the pulmonary chemoreflex characterized by tachypnea, bradycardia and hypotension. During the pulmonary chemoreflex, the time components (total cycle duration, inspiratory and expiratory times) of the cough motor pattern significantly decreased, whereas no consistent changes in peak phrenic and abdominal activity, peak tracheal pressure and number of coughs evoked by each stimulation trial were observed. At variance with previous findings in cats and dogs, the results show that tracheobronchial cough is not significantly reduced in the rabbit during PBG-induced chemoreflex. This study is the first to provide evidence supporting the hypothesis that the time components of the cough motor pattern are, to some extent, dependent upon the timing characteristics of the ongoing respiratory activity and suggests a novel mechanism leading to cough depression.
我们研究了在戊巴比妥麻醉、自主呼吸的家兔中，肺C纤维受体激活对气管支气管树机械刺激诱发的咳嗽反射所产生的影响。同时监测膈神经和腹肌活动以及气管和动脉血压。通过右心房注射苯双胍（PBG）激活肺C纤维受体，引发了以呼吸急促、心动过缓和低血压为特征的肺化学反射。在肺化学反射期间，咳嗽运动模式的时间成分（总周期持续时间、吸气和呼气时间）显著缩短，而膈神经和腹肌活动峰值、气管压力峰值以及每次刺激试验诱发的咳嗽次数均未观察到一致变化。与之前在猫和狗身上的研究结果不同，本研究结果表明，在PBG诱发的化学反射期间，家兔的气管支气管咳嗽并未显著减轻。本研究首次提供证据支持以下假设：咳嗽运动模式的时间成分在一定程度上依赖于当前呼吸活动的时间特征，并提出了一种导致咳嗽抑制的新机制。
