ACETYLCHOLINE AND SUBSTANCE-P STIMULATE BRONCHIAL EPITHELIAL-CELLS TORELEASE EOSINOPHIL CHEMOTACTIC ACTIVITY

We investigated a role of neuroregulation in the release of eosinophil chemotactic activity (ECA) from bovine bronchial epithelial cells (BB EC). BBEC were stimulated with acetylcholine (ACh) and substance P (SP ), and the supernatant fluids were tested for ECA by a blind-well chem otactic chamber technique. BBEC released ECA in response to ACh and SP in a dose-and time-dependent manner. Checkerboard analysis showed tha t ECA in regard to ACh and SP was chemotactic rather than chemokinetic . Partial characterization revealed that ECA involved both lipids and peptides. The release of ECA in response to ACh and SP was inhibited b y nonspecific and 5-specific lipoxygenase inhibitors and by cyclohexim ide (P < 0.01). Molecular-sieve column chromatography revealed that th ese mediators induced three molecular mass peaks (near 25 kDa, 9 kDa, and 400 Da, respectively). The lowest peak, which represented the pred ominant activity, was blocked by leukotriene B-4-receptor antagonist ( P < 0.01) but not by platelet-activating factor-receptor antagonist. T he release of leukotriene B-4 in the supernatant fluids was increased in response to ACh and SP stimulation (P < 0.01). Platelet-activating factor was not detected. These results raise the possibility of a role of neuroregulation for the elaboration of ECA in the airway.