Characterization of intrapulmonary, rapidly adapting receptors of XXXX .

@entity3265 @entity167 @entity235 @entity840 @entity1324 @entity95 @entity4543 @entity112 @entity3044
The activity of 33 afferent vagal fibers arising from rapidly adapting pulmonary stretch receptors in the lungs of 21 @entity840 was studied. These receptors were identified by their response to constant pressure hyperinflation and to negative pressure deflation of the lungs. The response was irregular bursts of action potentials with an adaptation index greater than 70% in 2s. Little or no activity was noted in these receptors during eupneic breathing. The conduction velocity of the afferent fibers from these receptors ranged from 3.1 to 57.1 m/s (mean = 20.2 +/- 5.1 SD). Receptors were stimulated by intravenous injection of @entity112 and also by vapors of @entity4543 , @entity167 , @entity1324 , @entity3265 , and cigarette smoke. Stimulation by the inhalation of the vapors usually occurred in the absence of any change in tracheal pressure or even when the tracheal pressure became slightly lower than before vapor challenge, thus suggesting a direct action. If an increase in tracheal pressure occurred, the discharge of the receptor began well in advance. However, stimulation of the receptor by @entity112 was always accompanied by significant increases in tracheal pressure. @entity3044 prevented the increase in tracheal pressures produced by @entity112 challenge. In addition, @entity3044 blocked the response of rapidly adapting receptors to @entity112 as well. @entity3044 had no effect on receptor response to the various vapors used in this study. Therefore, stimulation of rapidly adapting receptors by @entity112 seems to be dependent on an increase in tracheal pressure, while a direct action in indicated by several 'irritant' gases. The characteristics of the rapidly adapting receptors in @entity840 lungs are more closely related to the irritant receptor of the @entity95 and the cat than to the rapidly adapting receptors in lungs of @entity235 .
