Investigação do papel dos receptores glutamatérgicos do tipo ampa no colículo inferior sobre a catalepsia induzida pelo haloperidol em ratos
Arquivos
Data
2013-12-16
Autores
Tonelli, Luan Castro 
Orientadores
Santos, Ronaldo Vagner Thomatieli dos
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
O colículo inferior (CI) é uma estrutura mesencefálica primariamente envolvida no processamento da informação
auditiva, mas também integra informação sensorial de natureza aversiva. A estimulação elétrica ou química dessa
estrutura induz respostas típicas de medo tais como alerta, congelamento e fuga, eliciadas por ameaças ambientais.
Evidências científicas sugerem que o substrato neural responsável pelo comportamento defensivo no colículo inferior
pode também ser regulado por aminoácidos excitatórios uma vez que a microinjeção de NMDA nessa estrutura induz
comportamento defensivo caracterizado por corrida, levantamentos e saltos. Entretanto, a microinjeção de AP7, um
antagonista competitivo de receptores NMDA impede a expressão desses comportamentos. Tem sido demonstrado que
a estimulação do substrato neural do medo no colículo inferior causa um aumento significante nos níveis extracelulares
de dopamina em outras estruturas tais como o córtex frontal. Estudos prévios realizados em nosso laboratório mostram
que a microinjeção de antagonistas de receptores glutamatérgicos do tipo NMDA no CI é capaz de reverter a catalepsia
induzida pelo haloperidol. Mas ainda não se sabe se os receptores glutamatérgicos do tipo AMPA no CI também podem
ser responsáveis por modular o processo de catalepsia. O presente trabalho investigou se a microinjeção de DNQX, um
antagonista de receptores glutamatérgicos do tipo AMPA, diretamente no colículo inferior, foi capaz de influenciar a
catalepsia induzida pela administração sistêmica do neuroléptico haloperidol. Os animais foram submetidos a uma
cirurgia para implantação de uma cânula no CI e receberam microinjeções de DNQX (1,0μg/0,5μl e 2,5μg/0,5μl). Em
seguida foi realizada a administração sistêmica de haloperidol (1,0 mg/kg) e imediatamente após, os animais foram
colocados em uma arena onde foi realizada a avaliação da catalepsia. Os resultados mostram que a microinjeção de
DNQX, um antagonista de receptores AMPA diretamente no colículo inferior na dose de 1,0μg/0,5μl, pode reverter a
catalepsia induzida pelo haloperidol.
The inferior colliculus (IC) is a mesencephalic structure primarily involved in the processing of auditory information, but it also integrates sensory information of aversive nature. The electrical or chemical stimulation of this structure induces typical responses of fear, such as alert, freezing and fleeing,elicited by environmental threats. Scientific evidencesuggeststhat the neural substrate responsible for the defensive behaviour in the inferior colliculus can also be regulated by excitatory amino acidswhenthe microinjection of N-methyl-D-aspartate (NMDA) in this structure induces defensive behaviour such as running, standing up and jumps. However, the microinjection of AP7, a competitive antagonist of NMDA receptors, hinders the expression of these behaviours. It has been shown that the stimulation of the neural substrate of fear in the IC causes a significant increase in the extracelular levels of dopamine in other structures such as the frontal cortex.Previous studies carried out in our laboratory showed that the microinjection of NMDA glutamate receptor antagonists in the IC was able to reverse the catalepsy induced by haloperidol. But it is still unknown whether the AMPA glutamate receptors in the IC could also be responsible for modulating the catalepsy process. The present study investigated whether the microinjection of DNQX, which is an AMPAglutamate receptor antagonist, directly in the IC was able to influence the catalepsy induced by the systemic administration of the neuroleptichaloperidol. The animals were subjected to surgery to implant a cannula in the IC,and they received microinjections of DNQX (1.0μg/0.5μl and 2.5μg/0.5μl). Subsequently they received the systematic administration of haloperidol (1.0 mg/Kg), and were placed immediatly afterward in an arena where the catalepsyevaluation was performed. The results showed that the microinjection of DNQX, an antagonist of AMPA receptors, directly in the IC in a dose of 1.0μg/0.5μl, can reverse the catalepsy induced by haloperidol.
The inferior colliculus (IC) is a mesencephalic structure primarily involved in the processing of auditory information, but it also integrates sensory information of aversive nature. The electrical or chemical stimulation of this structure induces typical responses of fear, such as alert, freezing and fleeing,elicited by environmental threats. Scientific evidencesuggeststhat the neural substrate responsible for the defensive behaviour in the inferior colliculus can also be regulated by excitatory amino acidswhenthe microinjection of N-methyl-D-aspartate (NMDA) in this structure induces defensive behaviour such as running, standing up and jumps. However, the microinjection of AP7, a competitive antagonist of NMDA receptors, hinders the expression of these behaviours. It has been shown that the stimulation of the neural substrate of fear in the IC causes a significant increase in the extracelular levels of dopamine in other structures such as the frontal cortex.Previous studies carried out in our laboratory showed that the microinjection of NMDA glutamate receptor antagonists in the IC was able to reverse the catalepsy induced by haloperidol. But it is still unknown whether the AMPA glutamate receptors in the IC could also be responsible for modulating the catalepsy process. The present study investigated whether the microinjection of DNQX, which is an AMPAglutamate receptor antagonist, directly in the IC was able to influence the catalepsy induced by the systemic administration of the neuroleptichaloperidol. The animals were subjected to surgery to implant a cannula in the IC,and they received microinjections of DNQX (1.0μg/0.5μl and 2.5μg/0.5μl). Subsequently they received the systematic administration of haloperidol (1.0 mg/Kg), and were placed immediatly afterward in an arena where the catalepsyevaluation was performed. The results showed that the microinjection of DNQX, an antagonist of AMPA receptors, directly in the IC in a dose of 1.0μg/0.5μl, can reverse the catalepsy induced by haloperidol.
Descrição
Citação
TONELLI, Luan Castro. Investigação do papel dos receptores glutamatérgicos do tipo ampa no colículo inferior sobre a catalepsia induzida pelo haloperidol em ratos. 2013. 31 f. Trabalho de conclusão de curso de graduação (Educação Física) - Instituto de Saúde e Sociedade, Universidade Federal de São Paulo, Santos, 2013.