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Master's Dissertation
DOI
https://doi.org/10.11606/D.42.2012.tde-25072012-131207
Document
Author
Full name
Livia Silva Medeiros de Mesquita
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2012
Supervisor
Committee
Afeche, Solange Castro (President)
Amaral, Fernanda Gaspar do
Buonfiglio, Daniella do Carmo
Title in Portuguese
Ações da metilecgonidina sobre a síntese de melatonina na glândula pineal de ratos.
Keywords in Portuguese
Acetilcolina
Glândula pineal
Melatonina
Ratos
Receptores adrenérgicos
Abstract in Portuguese
A glândula pineal sintetiza o hormônio melatonina no período escuro. No rato, a ativação dos receptores a e b-adrenérgicos aumenta os níveis de AMPc, levando à síntese e ativação da enzima arilalquilamina-N-acetiltransferase (AANAT). A glândula recebe também inervação parassimpática, sendo inibitório o efeito da acetilcolina. A metilecgonidina (AEME) é o produto da pirólise da cocaína, quando esta é usada sob a forma de "crack". Neste trabalho estudamos os efeitos e os mecanismos de ação da AEME sobre a síntese da melatonina. Foram investigados a atividade da AANAT, o Ca2+, o AMPc e a viabilidade celular e a fragmentação do DNA. A AEME reduziu a síntese da melatonina in vivo e in vitro, sendo este efeito revertido pela atropina. A AEME induziu um aumento do Ca2+, não alterando o AMPc e a atividade da AANAT. A viabilidade celular e fragmentação do DNA não foram modificadas pela AEME. Em conclusão, a AEME reduz a síntese da melatonina, in vitro e in vivo, e a sua ação se dá por interferir com o sistema colinérgico muscarínico.
Title in English
Actions of the metilecgonidine on the syntesis of melatonin in the pineal gland of rats.
Keywords in English
Acetylcholine
Adrenergic receptors
Melatonin
Pineal gland
Rats
Abstract in English
The pineal gland synthesizes the hormone melatonin in the dark. In rats, the activation of a and b-adrenergic receptors increases cAMP levels and the synthesis and activity of arylalkylamine-N-acetyltransferase enzyme (AANAT). The pineal gland is also innervated by parasympathetic fibers, being inhibitory the effect of acetylcholine. Methylecgonidine (AEME) is the pyrolysis product of cocaine when it is used as "crack." In this work we studied the effects of AEME on the melatonin synthesis, in vitro and in vivo. We investigated AANAT activity, iCa2+, cAMP, cell viability and DNA fragmentation. AEME reduced melatonin synthesis in vivo and in vitro, and this effect was reversed by atropine. There was an increase in Ca2+, but not in cAMP or AANAT activity induced by AEME. Cell viability and DNA fragmentation were not affected by AEME. In conclusion, AEME reduced melatonin synthesis in vitro and in vivo, being this effect mediated by the muscarinic cholinergic system.
 
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Publishing Date
2012-08-15
 
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