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Nicotine activates and up-regulates nicotinic acetylcholine receptors in bronchial epithelial cells.
Fu, Xiao Wen; Lindstrom, Jon; Spindel, Eliot R.
Afiliación
  • Fu XW; Division of Neuroscience, Oregon National Primate Research Center, 505 NW 185th Ave., Beaverton, OR 97006, USA.
Am J Respir Cell Mol Biol ; 41(1): 93-9, 2009 Jul.
Article en En | MEDLINE | ID: mdl-19097990
Prenatal nicotine exposure impairs normal lung development and leads to diminished pulmonary function after birth. Previous work from our laboratory has demonstrated that nicotine alters lung development by affecting a nonneuronal cholinergic autocrine loop that is expressed in lung. Bronchial epithelial cells (BECs) express choline acetyltransferase, the choline high-affinity transporter and nicotinic acetylcholine (ACh) receptor (nAChR) subunits. We now demonstrate through a combination of morphological and electrophysiological techniques that nicotine affects this autocrine loop by up-regulating and activating cholinergic signaling. RT-PCR showed the expression of alpha 3, alpha 4, alpha 7, alpha 9, alpha 10, beta2, and beta 4 nAChR mRNAs in rhesus monkey lung and cultured BECs. The expression of alpha 7, alpha 4, and beta2 nAChR was confirmed by immunofluorescence in the cultured BECs and lung. The electrophysiological characteristics of nAChR in BECs were determined using whole-cell patch-clamp on cultured BECs. Both ACh and nicotine evoked an inward current, with a rapid desensitizing current. Nicotine induced inward currents in a concentration-dependent manner, with an EC(50) of 26.7 microM. Nicotine-induced currents were reversibly blocked by the nicotinic antagonists, mecamylamine, dihydro-beta-erythroidine, and methyllcaconitine. Incubation of BECs with 1 microM nicotine for 48 hours enhanced nicotine-induced currents by roughly 26%. The protein tyrosine phosphorylation inhibitor, genistein, increased nicotine-induced currents by 58% and enhanced methyllcaconitine-sensitive currents (alpha 7 nAChR activities) 2.3-fold, whereas the protein tyrosine phosphatase inhibitor, pervanadate, decreased the effects of nicotine. These results demonstrate that chronic nicotine exposure up-regulates nAChR activity in developing lung, and that nAChR activity can be further modified by tyrosine phosphorylation.
Asunto(s)

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Bronquios / Receptores Nicotínicos / Agonistas Nicotínicos / Comunicación Autocrina / Pulmón / Nicotina Límite: Animals Idioma: En Revista: Am J Respir Cell Mol Biol Asunto de la revista: BIOLOGIA MOLECULAR Año: 2009 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Estados Unidos

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Bronquios / Receptores Nicotínicos / Agonistas Nicotínicos / Comunicación Autocrina / Pulmón / Nicotina Límite: Animals Idioma: En Revista: Am J Respir Cell Mol Biol Asunto de la revista: BIOLOGIA MOLECULAR Año: 2009 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Estados Unidos