Melatonin modulates rat myotube-acetylcholine receptors by inhibiting calmodulin

Melatonin modulates rat myotube-acetylcholine receptors by inhibiting calmodulin

Author Almeida-Paula, L. D. de Google Scholar
Costa-Lotufo, L. V. Google Scholar
Ferreira, Z. S. Google Scholar
Monteiro, AEG Google Scholar
Isoldi, M. C. Google Scholar
Godinho, R. O. Google Scholar
Markus, R. P. Google Scholar
Institution Universidade de São Paulo (USP)
Univ Fed Ceara
Universidade Federal de São Paulo (UNIFESP)
Abstract Melatonin, the pineal gland hormone, modulates a-bungarotoxin sensitive nicotinic acetylcholine receptors in sympathetic nerve terminal, cerebellum and chick retina imposing a diurnal variation in functional responses [Markus, R.P., Zago, W.M., Cameiro, R.C., 1996. Melatonin modulation of presynaptic nicotinic acetylcholine receptors in the rat vas deferens. J. Pharmacol. Exp. Ther. 279, 18-22; Markus, R.P., Santos, J. M., Zago, W., Reno, L.A., 2003. Melatonin nocturnal surge modulates nicotinic receptors and nicotine-induced [(HI)-H-3] glutamate release in rat cerebellum slices. J. Pharmacol. Exp. Ther. 305, 525-530; Sampaio, L.F.S., Hamassaki-Britto, D.E., Markus, R.P., 2005. Influence of melatonin on the development of functional nicotinic acetylcholine receptors in cultured chick retinal cells. Braz. J. Med. Biol. Res. 38, 603-613]. Here we show that in rat myotubes forskolin and melatonin reduced the number of nicotinic acetylcholine receptors expressed in plasma membrane. in addition, these cells expressed melatonin MT1 receptors, which are known to be coupled to G(i)-protein. However, the pharmacological profile of melatonin analogs regarding the reduction in cyclic AMP accumulation and number of nicotinic acetylcholine receptors did not point to a mechanism mediated by activation of G(i)-protein coupled receptors. On the other hand, calmidazolium, a classical inhibitor of calmodulin, reduced in a similar manner both effects. Considering that one isoform of adenylyl cyclase present in rat myotubcs is regulated by Ca2+/calmodulin, we propose that melatonin modulates the number of nicotinic acetylcholine receptors via reduction in cyclic AMP accumulation. (c) 2005 Elsevier B.V. All rights reserved.
Keywords melatonin
nicotinic acetylcholine receptor
alpha-bungarotoxin
myotube culture
cyclic AMP
calmodulin
Language English
Date 2005-11-21
Published in European Journal of Pharmacology. Amsterdam: Elsevier B.V., v. 525, n. 1-3, p. 24-31, 2005.
ISSN 0014-2999 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 24-31
Origin http://dx.doi.org/10.1016/j.ejphar.2005.09.056
Access rights Closed access
Type Article
Web of Science ID WOS:000233711400004
URI http://repositorio.unifesp.br/handle/11600/28554

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