J. Tamaoki et al., EFFECT OF 5-HYDROXYTRYPTAMINE ON BIOELECTRIC PROPERTIES OF AIRWAY EPITHELIAL-CELLS IN CULTURE, Research communications in molecular pathology and pharmacology, 92(3), 1996, pp. 285-298
To elucidate whether 5-hydroxytryptamine (5-HT) affects airway epithel
ial electrolyte transport and, if so, what the mechanism of action is,
we studied the bioelectric properties of canine cultured tracheal epi
thelium under short-circuit conditions in vitro. Mucosal addition of 5
-HT dose-dependently increased short-circuit current (Isc), which was
accompanied by increases in transepithelial potential difference and c
ell conductance. In contrast, 5-HT had no effect on bioelectric proper
ties when it was added to the submucosal side. Pretreatment of cells w
ith amiloride potentiated the increase in Isc produced by 5-HT. In the
presence of diphenylamine-2-carboxylate or Cl-free medium, 5-HT decre
ased Isc from the baseline level. Incubation with BAPTA-AM but not dib
utyryl cAMP greatly attenuated the 5-HT-induced increase in amiloride-
insensitive portion of Isc. These results suggest that 5-HT inhibits N
a absorption and stimulates Cl secretion across canine tracheal epithe
lium and that the Cl secretion may be associated with elevation of int
racellular Ca2+ contents.