EFFECT OF ALPHA-ADRENERGIC STIMULATION ON MUCUS SECRETION AND ON ION-TRANSPORT IN CAT TRACHEA INVITRO

Abstract

In cat trachea mounted in Ussing chambers, the effects of an .alpha.-adrenergic agonist on mucus secretion measured with 35S bound to sulfated glycoproteins, and on fluxes of Na+ and Cl- measured with 22Na and 36Cl under open-circuit conditions were studied. Phenylephrine (10-5 M), increased bound 35S-secretion by 147 .+-. 24% (mean .+-. SE, no. = 13), increased .**GRAPHIC**. [unidirectional flux of Cl- from submucosa to lumen] from 2.54 .+-. 0.23 to 7.40 .+-. 1.19 .mu.eq/cm2 per h (no. = 6), and increased .**GRAPHIC**. [unidirectional flux of Na+ from submucosa to lumen] from 1.75 .+-. 0.36 to 7.25 .+-. 1.10 .mu.eq/cm2 per h (no. = 6). It decreased .**GRAPHIC**. [unidirectional flux of Cl- from lumen to submucosa] from 2.69 .+-. 0.41 to 2.46 .+-. 0.41 .mu.eq/cm2 per h, but did not change .**GRAPHIC**. [unidirectional flux of Na+ from lumen to submucosa]. The stimulatory effects of (10-5 M) phenylephrine were prevented by (10-5 M) phentolamine, but were unaffected by (10-5 M) propranolol. Terbutaline (10-5 M), a .beta.2-adrenergic agonist, only increased bound 35S secretion by 43 .+-. 7% (no. = 22) and only increased .**GRAPHIC**. from 3.76 .+-. 0.46 to 4.55 .+-. 0.41 .mu.eq/cm2 per h (no. = 6); it did not change the other fluxes. .alpha.-Adrenergic stimulation causes secretion of sulfated glycoproteins and ion-mediated movement of water into the cat trachea.