Papel da PKA cortical na formação da memória de reconhecimento de objetos

Abstract

Recognition memory is a central component of declarative memories. Failures in the processing of these memories lead to severe consequences that characterize the initial symptoms in patients with cognitive decline, such as Alzheimer's disease. The novel object recognition task is used to evaluate the molecular mechanisms involved in the processing of recognition memory which requires the detection of novelty in the environment. Different regions of the brain are required to discriminate objects. The medial prefrontal cortex (mPFC) and the hippocampus play distinct roles during the processing of this type of memory. Dopamine is important for novelty detection and signaling mediated by the activation of D1/D5 receptors is mediated by cAMP-activated protein kinase, PKA. The aim of this study was to evaluate the role of cortical PKA in the formation of object recognition memory in rats. Adult and middle-aged male and female Wistar rats were bilaterally implanted with cannulas in the mPFC. Our results show that, in rats, the consolidation of long-term object recognition memory requires PKA activation in the mPFC shortly after training. Sex, age and time of the light/dark cycle do not interfere with formation of this type of memory and PKA inhibition in these individuals also induces amnesia. PKA inhibition also prevents short-term object recognition memory formation. With these findings we can infer that PKA in the mPFC is essential for object recognition memory formation.