The lung strip: evaluation of a method to study contractility of pulmonary parenchyma.

Isolated strips of rabbit lung were examined as an in vitro model for assessment of the direct effect of pharmacologic agents on the pulmonary parenchyma. Changes in force of the strip were measured with an isometric force transducer. Histamine, acetylcholine and epinephrine elicited dose-related contractile responses. Morphological and immunohistochemical examination revealed three possible sources of force generation within the strip: airway smooth muscle, vascular smooth muscle, and interstitial actin-containing cells. Generation of force by the strip could reflect contraction of any combination of these three elements. Therefore, ascription of such contraction to peripheral airway smooth muscle alone is questionable. In order to assess the properties of the contractile elements within the strip, it is necessary to isolate and study them individually.