We examined Na efflux, as an indicator of electrolyte (or water) secretion from isolated feline tracheal submucosal glands. After incubation with 22NaCl-containing KRB solution (pH 7.4) at 37 degrees C, the 22Na-loaded glands were transferred to a superfusion apparatus in which perfusate was continuously pumped to the glands at a flow rate of 2.5 ml/min and sampled at 18-s intervals for 10-15 min. After 5 min of perfusion, a pharmacological or electrical field stimulation (FS) was given to the isolated glands. The instantaneous rate constant was calculated by measuring the radioactivity (counts/min) of each effluent sample. The mean rate constant of the base-line 22Na efflux was 0.21 min-1, which fell significantly to 0.03 min-1 after treatment with ouabain. Both methacholine and phenylephrine significantly accelerated the 22Na efflux to 3.6-fold and 1.8 times base-line efflux, respectively. FS produced a significant increase in the rate constant, and the increase was abolished by pretreatment with ouabain or tetrodotoxin. Further, atropine or phentolamine significantly suppressed the FS-evoked increase in the rate constant to 76 and 84%, respectively, of the maximal response evoked by FS alone. These results indicate that Na efflux from feline tracheal submucosal glands, which is dependent on ouabain-sensitive Na-K-ATPase activity in the secretory cells, is stimulated by both cholinergic and alpha-adrenergic agonists.