抄録
Rats have been extensively used as a model of obstructive lung disease although information is limited. We therefore analyzed lung function, in particular flow-volume <FV> curves, in rats using a body-surface pressure ventilator. Male Wistar rats were anesthetized without paralysis, intratracheally intubated, and kept in the supine position. The rats were ventilated using a cyclic extrapulmonary pressure change of -25 and 0 cmH
2O in the tightly sealed chamber. After rat's respiratory phase was locked to ventilator's cycle, FV curves were obtained using the pressure change of -25 and +60 cmH
2O in the same chamber. Then the procedures were repeated after bilateral vagotomy. The mean values of the forced vital capacity <FVC> and the peak expiratory flow rate <PEFR> were 7.9 ml, 80 ml/sec respectively. The shape of FV curve was quite different from that of man. It consists of an ascending limb <part I>, steeply descending limb <part II> followed by a mildly descending limb <part III>. They were 63%, 15% and 22% of FVC respectively. When the positive pressure increased, PEFR became higher and the part I became shorter, but the shape and length of part III were not affected, i.e., effort-independent part. Bilateral vagotomy increased the PEFR by 7%, but did not change the FRC significantly. After vagotomy part I became shorter while part III became longer. Vagally-mediated descending signals appear to regulate calibers of both large and small airways in the rat.
[J Physiol Sci. 2007;57 Suppl:S215]
