Comparison of the effects of nicotine upon the transcellular electrical resistance and sucrose permeability of human ECV304/rat C6 co-cultures and human CaCo 2 cells

Abstract

It is now well established that nicotine adversely affects the integrity of the blood–brain barrier (BBB). In contrast, nicotine has been reported to increase the transendothelial electrical resistance (TEER) of CaCo 2 colon cancer cells. In the present study, the effects of nicotine upon the TEER and sucrose permeability of ECV304/C6 co-cultures and, for comparative purposes, CaCo 2 cells has been investigated. Neither ECV304 nor C6 cells were found to express measurable membrane levels of nicotinic acetylcholine receptors, as assessed by [ 3H]–epibatidine binding. Nicotine treatment (0.01–1 μM) for up to 48 h had little or no effect upon the TEER or sucrose permeability of either ECV304/C6 co-cultures or CaCo 2 cells. It is concluded that in contrast to the situation for the BBB, ECV304 cells lack nicotinic acetylcholine receptors and the barrier properties of ECV304/C6 co-cultures are not affected to any important extent by nicotine. This study underlines the conclusions made by other authors that the ECV304/C6 co-culture system is of limited validity as a model of the BBB.