Assessment of serotonergic system in formation of memory and learning.

J C Da Silva,C A M Amorim,E M Trindade Filho,L I Zambrano,G P Rodrigues,J Dal Pai

doi:10.1590/1519-6984.170952

Abstract

We evaluated the involvement of the serotonergic system on memory formation and learning processes in healthy adults Wistar rats. Fifty-seven rats of 5 groups had one serotonergic nuclei damaged by an electric current. Electrolytic lesion was carried out using a continuous current of 2mA during two seconds by stereotactic surgery. Animals were submitted to learning and memory tests. Rats presented different responses in the memory tests depending on the serotonergic nucleus involved. Both explicit and implicit memory may be affected after lesion although some groups showed significant difference and others did not. A damage in the serotonergic nucleus was able to cause impairment in the memory of Wistar. The formation of implicit and explicit memory is impaired after injury in some serotonergic nuclei.

Highlights

The main subcortical input to the hippocampal region comes from fimbria-fornix pathway, which is involved in explicit and implicit memory processes (Guillazo-Blanch et al, 2002; Morrell, 2011)
We describe the involvement of the serotonergic system with memory formation and learning processes in the rat
Our findings showed that the time spent for the rat to reach the food on the classic maze and the platform in the Morris water maze tests were different among groups

Summary

Introduction

The main subcortical input to the hippocampal region comes from fimbria-fornix pathway, which is involved in explicit and implicit memory processes (Guillazo-Blanch et al, 2002; Morrell, 2011). The hippocampi are often reported as the generator of rhythms related with learning and memory due to its involvement with neuronal plasticity known as short- and long-term potentiation (Beierlein et al, 2003; Ghaderi et al, 2016; Dittman et al, 2000; Sheikhzadeh et al, 2015). Facilitation of synaptic plasticity may occur by repeated activations and increase of neurotransmitter release, either by saturating the calcium buffer or increasing its concentration in the presynaptic terminal of the neuron. We describe the involvement of the serotonergic system with memory formation and learning processes in the rat

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Results

Conclusion