Caracterização de arranjos neurais da amídala basolateral envolvidos nos processos de memórias relacionadas ao treino e extinção da autoadministração operante de etanol
Data
2022-09-06
Autores
Yokoyama, Thais Suemi 
Orientadores
Cruz, Fabio Cardoso
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
O etanol é a droga de abuso mais utilizada no mundo. O transtorno por uso dessa
substância é considerado grande problema de saúde pública. Os tratamentos deste
transtorno são marcados por altos índices de recaída. Um dos principais gatilhos para a
precipitação da recaída é a exposição do indivíduo aos contextos associados ao uso
dessa droga. Estudos recentes, demonstram que essas associações são armazenadas
por pequenos grupos neurais seletivamente ativados e conectados entre si através de
sinapses fortes, chamados do inglês de neuronal ensembles. Evidências sugerem que
neuronal ensembles da amídala basolateral poderiam armazenar as associações
relacionados a reinstalação e extinção de comportamentos de busca de drogas. Ainda,
estudos sugerem que o aumento da ativação do sistema CRFérgico estaria relacionado
com comportamentos relacionados ao transtorno por uso de etanol. Assim, o objetivo do
presente estudo foi avaliar a participação de pequenos grupos neurais seletivamente
ativados, da amídala basolateral na extinção e reinstalação da busca de etanol induzida
pelo contexto em ratos e mudanças na expressão gênica de proteínas do sistema
CRFérgico neste comportamento. Para tanto, ratos foram treinados a autoadministrarem
etanol 10% em um ambiente, denominado de “Contexto A”. Em seguida, este
comportamento foi extinto, na ausência da droga e sob punição (os animais recebiam
água, solução de quinino 1mg/L ou etanol 10% + quinino 1mg/L), em um ambiente
distinto, denominado de Contexto B. Por fim, a capacidade do contexto de induzir a
reinstalação da busca por etanol, foi avaliada expondo os animais aos contextos A ou B,
porém sem a presença de reforço ou punição. Por meio desse protocolo, avaliamos: a) o
número e porcentagem de células positivas para Fos na amídala basolateral e central
durante a reinstalação da busca de etanol, induzida pelo contexto; b) os fenótipos dos
neurônios da amídala basolateral e central envolvidos nesse comportamento; c) A
participação funcional de neuronal ensembles da amídala basolateral nos processos de
extinção e busca de etanol; d) a seletividade da ativação neural dessa estrutura
encefálica, nesses comportamentos; e) alterações na expressão gênica do hormônio
liberador de corticotrofina (CRF); do receptor de CRF do tipo 1 (CRFr1) e da proteína de
ligação ao CRF (CRF-BP), na amídala durante o teste de reinstalação induzida por
contexto. Nossos resultados demonstraram que: a) independente da solução recebida, na
extinção (quinino, quinino + etanol ou água) o contexto foi capaz de reinstalar a busca de
etanol; b) não foram encontradas alterações no número e porcentagem de células
positivas para Fos na amídala basolateral e central, entre os grupos e contextos; c)
independente da punição ou não, uma pequena porcentagem de neurônios foi ativado na
amídala basolateral e central durante o teste de reinstalação da busca de etanol induzida
pelo contexto; d) Durante a exposição dos animais aos ambientes de treino ou extinção, a
ativação de neurônios glutamatérgicos e GABAérgicos foi semelhante entre os grupos; e)
a inativação de neuronal ensembles relacionados ao contexto de extinção do treino de
autoadministração operante de etanol, não modificou os comportamentos de extinção ou
reinstalação da busca de etanol; f) as porcentagens de co-localização dos neurônios
ativados entre a exposição ou reexposição aos contextos foram: Contexto B e Contexto
B: 30,8%; Contexto B e Contexto A: 26,9%; Contexto A e Contexto A: 31,8%; Contexto A
e Contexto B: 30,5%; gaiola moradia e gaiola moradia: 50,40%; e g) não houve a
influência dos contextos na expressão gênica do CRF, CRFr1 e CRF-BP. Por fim, estes
resultados sugerem que a amídala basolateral parece armazenar conjuntos neuronais
que medeiam as memórias associativas relacionadas aos comportamentos de extinção e
de busca de etanol
Ethanol is the most used drug of abuse in the world. Substance use disorders are considered a significant public health problem. High rates of relapse mark the treatment of this disorder. The exposure of the individual to the contexts associated with the drug is considered the main factor in induced relapse. Studies suggest that drug-cue memories are encoded by a specific small and sparsely distributed population of neurons, called neuronal ensembles. In addition, increased levels of activation of the CRFergic system seem to be correlated with behaviors related to alcohol use disorder. We aimed to evaluate the participation of basolateral amygdala neuronal ensembles in the extinction and reinstatement of ethanol seeking induced by the context and to assess changes in the CRFergic system gene expression associated with the reinstatement context-induced. For that, rats were trained to self-administer 10% ethanol in an environment called “Context A.” Then, this behavior was extinguished, in the absence of the drug and under punishment (the animals received either water or 1g/L quinine solution or 10% ethanol + 1g/L quinine), in a different environment, called Context B. Finally, context-induced reinstatement of ethanol-seeking was evaluated by exposing the animals to contexts A or B but without the presence of reinforcement or punishment. Through this protocol, we evaluated: a) the activation and the percentage of neurons activated on the basolateral and central amygdala during context-induced ethanol-seeking behavior; b) the phenotype of basolateral and central amygdala neurons involved in this behavior; c) The participation of basolateral amygdala neuronal ensembles in context-induced extinction and ethanol seeking; d) the selectivity of neural activation of this brain area, in these behaviors; and e) to assess changes in corticotrophin release factor (CRF); CRF receptor type 1 (CRFr1) e CRF Binding Protein (CRF-BP)m gene expression associated with the reinstatement context-induced. Our results showed that: a) regardless of the solution received in the extinction test, the context was able to reinstall the ethanol-seeking behavior; b) no alterations were found in the number and percentage of Fos positive cells in the basolateral and central amygdala, between groups and contexts; c) regardless of punishment or not, a small percentage of neurons were activated in the basolateral and central amygdala during the context-induced the reinstatement of ethanol-seeking, after punishment-imposed abstinence; d) During the exposure of the animals to the training or extinction context, the activation of glutamatergic or GABAergic neurons were similar between the groups; e) the inactivation of neuronal ensembles associated with the extinction or training context did not modify the extinction or reinstatement of ethanol seeking; f) the percentages of co-location of reactivated neurons in Context B and Context B groups was 30.8%; Context B and Context A was 26.9%; Context A and Context A was 31.8%; Context A and Context B was 30.5%; home-cage and home-cage was 50.40%; g) the contexts did not induced changes in the expression of CRF, CRFr1 and CRF-BP. Our results suggest that the basolateral amygdala may intermingle neuronal ensembles related to extinction and ethanol-seeking behaviors.
Ethanol is the most used drug of abuse in the world. Substance use disorders are considered a significant public health problem. High rates of relapse mark the treatment of this disorder. The exposure of the individual to the contexts associated with the drug is considered the main factor in induced relapse. Studies suggest that drug-cue memories are encoded by a specific small and sparsely distributed population of neurons, called neuronal ensembles. In addition, increased levels of activation of the CRFergic system seem to be correlated with behaviors related to alcohol use disorder. We aimed to evaluate the participation of basolateral amygdala neuronal ensembles in the extinction and reinstatement of ethanol seeking induced by the context and to assess changes in the CRFergic system gene expression associated with the reinstatement context-induced. For that, rats were trained to self-administer 10% ethanol in an environment called “Context A.” Then, this behavior was extinguished, in the absence of the drug and under punishment (the animals received either water or 1g/L quinine solution or 10% ethanol + 1g/L quinine), in a different environment, called Context B. Finally, context-induced reinstatement of ethanol-seeking was evaluated by exposing the animals to contexts A or B but without the presence of reinforcement or punishment. Through this protocol, we evaluated: a) the activation and the percentage of neurons activated on the basolateral and central amygdala during context-induced ethanol-seeking behavior; b) the phenotype of basolateral and central amygdala neurons involved in this behavior; c) The participation of basolateral amygdala neuronal ensembles in context-induced extinction and ethanol seeking; d) the selectivity of neural activation of this brain area, in these behaviors; and e) to assess changes in corticotrophin release factor (CRF); CRF receptor type 1 (CRFr1) e CRF Binding Protein (CRF-BP)m gene expression associated with the reinstatement context-induced. Our results showed that: a) regardless of the solution received in the extinction test, the context was able to reinstall the ethanol-seeking behavior; b) no alterations were found in the number and percentage of Fos positive cells in the basolateral and central amygdala, between groups and contexts; c) regardless of punishment or not, a small percentage of neurons were activated in the basolateral and central amygdala during the context-induced the reinstatement of ethanol-seeking, after punishment-imposed abstinence; d) During the exposure of the animals to the training or extinction context, the activation of glutamatergic or GABAergic neurons were similar between the groups; e) the inactivation of neuronal ensembles associated with the extinction or training context did not modify the extinction or reinstatement of ethanol seeking; f) the percentages of co-location of reactivated neurons in Context B and Context B groups was 30.8%; Context B and Context A was 26.9%; Context A and Context A was 31.8%; Context A and Context B was 30.5%; home-cage and home-cage was 50.40%; g) the contexts did not induced changes in the expression of CRF, CRFr1 and CRF-BP. Our results suggest that the basolateral amygdala may intermingle neuronal ensembles related to extinction and ethanol-seeking behaviors.
Descrição
Citação
YOKOYAMA, T.S. Caracterização de arranjos neurais da amídala basolateral envolvidos nos processos de memórias relacionadas ao treino e extinção da autoadministração operante de etanol. São Paulo, 2022. 137 f. Tese (Doutorado em Farmacologia) - Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP). São Paulo, 2022.