Bases neurofisiológicas da dependência do tabaco
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Data
2005-10-01
Autores
Planeta, Cleopatra da Silva [UNESP]
Cruz, Fábio C.
Título da Revista
ISSN da Revista
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Editor
Universidade de São Paulo (USP), Faculdade de Medicina
Resumo
A maioria dos estudos pré-clínicos e clínicos aponta a nicotina como o principal agente responsável pelo desenvolvimento da dependência ao tabaco. Muitos trabalhos têm demonstrado que as bases neurais da dependência à nicotina são semelhantes àquelas das outras drogas de abuso. A nicotina induz preferência condicionada por lugar e auto-administração e, portanto, atua como reforçador positivo, esse efeito parece ser mediado pelo sistema dopaminérgico mesolímbico. A nicotina também induz à sensibilização comportamental que é provavelmente resultante de alterações da expressão gênica do núcleo acumbens induzidas pela exposição prolongada a essa substância. A suspensão do uso de nicotina resulta em síndrome de abstinência. As evidências indicam que esses sinais e sintomas sejam mediados por receptores colinérgicos nicotínicos centrais e periféricos. Outros neurotransmissores, como por exemplo a serotonina e os peptídeos opióides, também podem estar envolvidos na mediação da dependência e síndrome de abstinência à nicotina. A revisão da literatura mostra a complexidade dos efeitos da nicotina no organismo. A integração entre as abordagens comportamental, neuroquímica e molecular possibilitará a compreensão dos mecanismos neurais da dependência ao tabaco e fornecerá as bases para o desenvolvimento racional de agentes terapêuticos que possam ser utilizados para o tratamento da dependência e síndrome de abstinência ao tabaco.
It is generally accepted that nicotine is the major component in tobacco smoke responsible for addiction. Several studies have demonstrated that the neural mechanisms underlying nicotine addiction have much in common with those underlying the mechanisms of addiction to other drugs. Thus, it has been shown that nicotine induces conditioning place preference and self-administration across many species. Repeated treatment with nicotine also induces behavioral sensitization in rodents. These behavioral effects of nicotine seem to mediate through the meso limbic dopamine system. Smoke cessation results in an abstinence syndrome that seems to be mediated by both peripheral and central nicotinic acetylcholine receptors. In addition, other neurotransmitters systems are involved in the mediation of nicotine addiction and withdrawal. The review of the literature evidences the complexity of the behavioral, neurochemical and molecular effects of nicotine. The integration of nicotine studies across all levels will lead to a better understanding of the neurobiological mechanisms underlying the addictive actions of nicotine. The understanding of such mechanisms is crucial to the development of pharmacological agents for the treatment of tobacco addiction and withdrawal.
It is generally accepted that nicotine is the major component in tobacco smoke responsible for addiction. Several studies have demonstrated that the neural mechanisms underlying nicotine addiction have much in common with those underlying the mechanisms of addiction to other drugs. Thus, it has been shown that nicotine induces conditioning place preference and self-administration across many species. Repeated treatment with nicotine also induces behavioral sensitization in rodents. These behavioral effects of nicotine seem to mediate through the meso limbic dopamine system. Smoke cessation results in an abstinence syndrome that seems to be mediated by both peripheral and central nicotinic acetylcholine receptors. In addition, other neurotransmitters systems are involved in the mediation of nicotine addiction and withdrawal. The review of the literature evidences the complexity of the behavioral, neurochemical and molecular effects of nicotine. The integration of nicotine studies across all levels will lead to a better understanding of the neurobiological mechanisms underlying the addictive actions of nicotine. The understanding of such mechanisms is crucial to the development of pharmacological agents for the treatment of tobacco addiction and withdrawal.
Descrição
Palavras-chave
Nicotina, tabaco, dependência, síndrome de abstinência, Nicotine, tobacco, addiction, abstinence syndrome
Como citar
Revista de Psiquiatria Clínica. Faculdade de Medicina da Universidade de São Paulo, v. 32, n. 5, p. 251-258, 2005.