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Localy synthesized angiotensin modulates pineal melatonin generation

S H J Santos L Santos-Campos; O Baltau; Michael Bader; Lisete Compagno Michelini; S C Afeche; José Cipolla Neto; Congresso do Instituto de Ciências Biomédicas (3. 2001 São Paulo)

Resumos São Paulo: Comissão de Cultura e Extensão Universitária do ICB/USP, 2001

São Paulo Comissão de Cultura e Extensão Universitária do ICB/USP 2001

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  • Título:
    Localy synthesized angiotensin modulates pineal melatonin generation
  • Autor: S H J Santos
  • L Santos-Campos; O Baltau; Michael Bader; Lisete Compagno Michelini; S C Afeche; José Cipolla Neto; Congresso do Instituto de Ciências Biomédicas (3. 2001 São Paulo)
  • Assuntos: FISIOLOGIA
  • É parte de: Resumos São Paulo: Comissão de Cultura e Extensão Universitária do ICB/USP, 2001
  • Descrição: Indroduction: We aimed at studying the relative significance and the mechanisms by which the renin-angiotensin system (RAS) participates in the pineal melatonin (MEL) production. MEL and metoxy-indole production were determined in pineal gland culture after angiotensin AT1-receptor blockade with Losartan (LOS). To test the in vivo relevance of the local RAS, pineal MEL and its indole precursors were determined at transgenic rats with inhibited production of angiotensinogen in astrocytes, TGR(ASrAOGEN). Methods and Results: Wistar rats were decapitated and the glands were placed in a modified BGJb medium. After 48h of culture they were submitted to NA stimulation with or without AT1 receptors blockade by LOS. MEL content (assayed by HPLC-ED) was significantly decreased by AT1-receptor blockade (9.76±0.69 ng/gland vs. 14.43±1.21 in untreated glands, respectively, p=0.0003). LOS produced a significant decrease of pineal 5-HTP, 5-HT, 5-HIAA, NAS. MEL in TGR (ASrAOGEN) is significantly decreased in comparison with control rats (2.88±0.12 ng/gland vs. 3.49±0.31 ng/gland, p<0.05). The pineal content of the precursor indoles in TGR(ASrAOGEN) rats was significantly decreased in comparison to the control rats to a similar extent as the LOS effects in pineal culture. The levels of 5-HTP in the pineals of TGR(ASrAOGEN) rats were decreased to 76% of the control rats. Conclusions: Our results demonstrate that a local RAS is exerting a tonic modulation of indole synthesis
    by influencing the activity of tryptophan hydroxylase via AT1-receptors. Furthermore, our data provide support for important neuromodulatory role of astroglia in the pineal MEL synthesis, as it is, in the pineal gland, the cell type synthesizing the precursor molecule of the RAS
  • Editor: São Paulo Comissão de Cultura e Extensão Universitária do ICB/USP
  • Data de criação/publicação: 2001
  • Formato: 1 v. pôster 261.
  • Idioma: Inglês
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  • Realização: ABCD-USP USP   Logos de Redes Sociais: Freepik

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