Involvement Of Cholinergic Receptors In The Positive Effect Of Sodium Benzoate On Memory, Electrical Activity Of CA1 Pyramidal Neurons And Biochemical Factors In Male Parkinson's Disease Rats

Abstract

Thinking and memory problems are among the most worrisome potential Parkinson's disease (PD) symptoms. Given their significant impact on function and quality of life, understanding and treating the range of cognitive changes in Parkinson's is a top priority for researchers. The main cause of Parkinson's disease is the destruction of dopaminergic neurons in Substantia Nigra Pars Compacta (SNc). Considering the positive effects of sodium benzoate (NAB) on the central nervous system, the present study was performed to investigate the possibility of interference of cholinergic receptors on the positive effects of this drug. This experimental study was performed in two sections: electrophysiological and behavioral studies. In each section, the groupings were similar: Control group, Rotenone group (2mg/kg/19days/48h as IP), Solvent rotenone group, Rotenone group + Sodium benzoate (100 mg/kg/7days orally), Rotenone group + Sodium benzoate + Scopolamine (125nmol as Intracerebral injection), Rotenone group + Scopolamine + Sodium benzoate. (The number of animals in each group will be 8). At the beginning of the study, a Parkinson's disease-like model was developed by rotenone injection, and the model was confirmed through motor behavior and histological studies. Animal memory was assessed using step-through, then a single-unit recording method was used using an electro module and eProbe software to evaluate the electrical activity of pyramidal neurons in the CA1 region of the hippocampus. Finally, cytokines TNFα and IL-1, BDNF expression, and ROS levels were measured in the animal hippocampus. This study showed that in both parts, sodium benzoate was able to significantly improve the destructive effects of rotenone (P≤0.05). The use of scopolamine before applying NAB in electrophysiological and memory assessments could effectively reduce the positive effects of sodium benzoate (P≤0.05). But in biochemical studies, only when scopolamine was used before NAB prevented the positive effects of NAB (P≤0.05) and after NAB injection did not affect the results. The present study results showed that NAB could be at least partially a suitable option for treating rotenone-induced symptoms in male rats. This positive effect of rotenone appears to be partly due to the intervention of cholinergic receptors, as the use of scopolamine as a muscarinic receptor antagonist prevents the positive effects of NAB.