Effects of estrogen on intracellular signaling pathways linked to activation of muscarinic acetylcholine receptors and on acetylcholinesterase activity in rat hippocampus

Effects of estrogen on intracellular signaling pathways linked to activation of muscarinic acetylcholine receptors and on acetylcholinesterase activity in rat hippocampus

Author Santos Pereira, Renato Tavares dos Google Scholar
Porto, Catarina Segreti Autor UNIFESP Google Scholar
Godinho, Rosely Oliveira Autor UNIFESP Google Scholar
Francis Abdalla, Fernando Mauricio Google Scholar
Institution Inst Butantan
Universidade Federal de São Paulo (UNIFESP)
Abstract The aim of the present study was to investigate the effects of estrogen lack and estrogen replacement on the production of total [H-3]inositol phosphate ([H-3]IP) induced by the activation of muscarinic acetylcholine receptors (mAChRs) and on the mechanisms for inactivation of acetylcholine. Hippocampi were obtained from rats in proestrus (PE), ovariectomized for 15 days (C15), ovariectomized for 15 days and then treated with 17 beta-estradiol for 7 days (E7) and ovariectomized and immediately treated with 17 beta-estradiol for 21 days (E21). Ovariectomy did not change the basal level of total [H-3]IP in the hippocampus. 17 beta-Estradiol replacement (E7 and E21) reduced the basal level of total [H-3]IP. in all experimental groups, carbachol (CCh) caused a concentration -dependent rise in total [H-3]IP. the maximum effect was reached with 10(-4) M CCh. the response to 10(-4) M CCh in the hippocampi from C15 and E7 rats was twofold higher than in hippocampi from PE and E21 animals and was blocked by pirenzepine, but not by methoctramine. Ovariectomy or 17 beta-estradiol treatment for 7 days did not change neither the total acetylcholinesterase (AChE) activity nor the relative amount of mono- and dimeric G(1)/G(2) and tetrameric G(4) globular forms. Conversely, hormonal treatment for 21 days induced an increase in AChE activity of G(1)/G(2) and G(4) forms, indicating that 17 beta-estradiol stimulates both synthesis and assembly of AChE molecular forms. the present results suggest that the duration and/or a critical period with regard to the initiation of estrogen therapy are important to regulate the function of mAChRs and AChE activity in female rat hippocampus. (C) 2008 Elsevier Inc. All rights reserved.
Keywords muscarinic acetylcholine receptors
hippocampus
estrogen
ovariectomy
inositol phosphate
acetylcholinesterase
Language English
Date 2008-05-01
Published in Biochemical Pharmacology. Oxford: Pergamon-Elsevier B.V., v. 75, n. 9, p. 1827-1834, 2008.
ISSN 0006-2952 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 1827-1834
Origin http://dx.doi.org/10.1016/j.bcp.2008.01.016
Access rights Closed access
Type Article
Web of Science ID WOS:000255849400014
URI http://repositorio.unifesp.br/handle/11600/30635

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