QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: jpet.103.065037v1 310/1/52    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Liu, R.-H. Articles by Matsukura, S. Search for Related Content PubMed PubMed Citation Articles by Liu, R.-H. Articles by Matsukura, S.

CELLULAR AND MOLECULAR

The Expression and Functional Role of Nicotinic Acetylcholine Receptors in Rat Adipocytes

Third Department of Internal Medicine, Miyazaki Medical College, Miyazaki University, Kiyotake, Miyazaki, Japan

To clarify whether nicotine has a direct effect on the function of adipocytes, we evaluated nicotinic acetylcholine receptor (nAChR) expression in adipocytes by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunocytochemistry and the direct effects of nicotine on the production of adipocytokines by enzyme-linked immunosorbent assay and Western blot analysis. Receptor binding assays were performed using [³H]nicotine. RT-PCR studies revealed that 1–7, 9, 10, 1–4, , and subunit mRNAs are expressed in adipocytes. Immunocytochemical experiments also suggested the presence of 7 and 2 subunits. The receptor binding assay revealed a binding site for nicotine (K_d = 39.2 x 10^-9 M) on adipocytes. Adipocytes incubated with nicotine for 12 and 36 h released tumor necrosis factor- (TNF-), adiponectin, and free fatty acid (FFA) into the medium in a dose-dependent manner with increasing nicotine concentration from 6 x 10^-8 to 6 x 10^-4 M. However, TNF- protein levels in adipocytes incubated for 12 and 36 h decreased in a dose-dependent manner with increasing nicotine concentration from 6 x 10^-8 to 6 x 10^-4 M. These results show that adipocytes have functional nAChRs and suggest that nicotine reduces TNF- protein production in adipocytes through the activation of nAChRs. Nicotine may temporarily lower insulin sensitivity by stimulating the secretion of TNF- and FFA, whereas long-term direct stimulation of nAChRs by nicotine in addition to autonomic nervous system stimulation may contribute to better insulin sensitivity in vivo through a modulated secretion of adipocytokines.

Address correspondence to: Dr. Masanari Mizuta, Third Department of Internal Medicine, Miyazaki Medical College, Miyazaki University, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan. E-mail: mmizuta{at}fc.miyazaki-med.ac.jp

This article has been cited by other articles:

				M. M. Yeboah, X. Xue, M. Javdan, M. Susin, and C. N. Metz Nicotinic acetylcholine receptor expression and regulation in the rat kidney after ischemia-reperfusion injury Am J Physiol Renal Physiol, September 1, 2008; 295(3): F654 - F661. [Abstract] [Full Text] [PDF]

				A. Kalsbeek, F. Kreier, E. Fliers, H. P. Sauerwein, J. A. Romijn, and R. M. Buijs Minireview: Circadian Control of Metabolism by the Suprachiasmatic Nuclei Endocrinology, December 1, 2007; 148(12): 5635 - 5639. [Abstract] [Full Text] [PDF]

				Z. An, H. Wang, P. Song, M. Zhang, X. Geng, and M.-H. Zou Nicotine-induced Activation of AMP-activated Protein Kinase Inhibits Fatty Acid Synthase in 3T3L1 Adipocytes: A ROLE FOR OXIDANT STRESS J. Biol. Chem., September 14, 2007; 282(37): 26793 - 26801. [Abstract] [Full Text] [PDF]

				Y. Iwashima, T. Katsuya, K. Ishikawa, I. Kida, M. Ohishi, T. Horio, N. Ouchi, K. Ohashi, S. Kihara, T. Funahashi, et al. Association of Hypoadiponectinemia With Smoking Habit in Men Hypertension, June 1, 2005; 45(6): 1094 - 1100. [Abstract] [Full Text] [PDF]

				B. B. Duncan, M. I. Schmidt, J. S. Pankow, H. Bang, D. Couper, C. M. Ballantyne, R. C. Hoogeveen, and G. Heiss Adiponectin and the Development of Type 2 Diabetes: The Atherosclerosis Risk in Communities Study Diabetes, September 1, 2004; 53(9): 2473 - 2478. [Abstract] [Full Text] [PDF]