The Difference between Anxiolytic and Anxiogenic Effects Induced by Acute and Chronic Alcohol Exposure and Changes in Associative Learning and Memory Based on Color Preference and the Cause of Parkinson-Like Behaviors in Zebrafish.

Xiang Li,Di Chen,Yuan Zhang,Xi-Zeng Feng,Ming-Zhu Sun,Xu Li,Dong-Yan Chen,Yi-Xiang Li,Xin Zhao,Nicholas S Foulkes

doi:10.1371/journal.pone.0141134

Abstract

We describe an interdisciplinary comparison of the effects of acute and chronic alcohol exposure in terms of their disturbance of light, dark and color preferences and the occurrence of Parkinson-like behavior in zebrafish through computer visual tracking, data mining, and behavioral and physiological analyses. We found that zebrafish in anxiolytic and anxious states, which are induced by acute and chronic repeated alcohol exposure, respectively, display distinct emotional reactions in light/dark preference tests as well as distinct learning and memory abilities in color-enhanced conditional place preference (CPP) tests. Additionally, compared with the chronic alcohol (1.0%) treatment, acute alcohol exposure had a significant, dose-dependent effect on anxiety, learning and memory (color preference) as well as locomotive activities. Acute exposure doses (0.5%, 1.0%, and 1.5%) generated an “inverted V” dose-dependent pattern in all of the behavioral parameters, with 1.0% having the greatest effect, while the chronic treatment had a moderate effect. Furthermore, by measuring locomotive activity, learning and memory performance, the number of dopaminergic neurons, tyrosine hydroxylase expression, and the change in the photoreceptors in the retina, we found that acute and chronic alcohol exposure induced varying degrees of Parkinson-like symptoms in zebrafish. Taken together, these results illuminated the behavioral and physiological mechanisms underlying the changes associated with learning and memory and the cause of potential Parkinson-like behaviors in zebrafish due to acute and chronic alcohol exposure.

Highlights

The abuse or misuse of alcohol, such as alcoholism or alcohol dependence syndrome, has many negative effects on society and individual people [1]
Effects of acute and chronic alcohol treatment on the anxiety state in zebrafish The effects of acute and chronic alcohol exposure on eight behavioral parameters of the light/ dark preference test are illustrated as ball plot graphs with each ball representing a particular acute or chronic alcohol concentration (Fig 1)
The analysis of the “Time spent in light compartment” (Fig 1a) and “Distance moved in light compartment” (Fig 1c) demonstrated that zebrafish treated with either acute 0.5%,1.0%,1.5% or chronic 1.0% alcohol spent more time in the light compartment compared to the control, indicating a general anxiolytic effect of both acute and chronic alcohol

Summary

Introduction

The abuse or misuse of alcohol, such as alcoholism or alcohol dependence syndrome, has many negative effects on society and individual people [1]. Acute excessive consumption or chronic alcohol abuse can interact with multiple biochemical targets in several regions of the brain and affect mood, learning and memory [3]. The acute consumption of alcohol at relatively low concentrations may cause some “pleasurable” effects, such as euphoria, relaxation, and the relief of stress or anxiety [4] while chronic alcohol intake results in dependence, which manifests as increased stress and anxiety without alcohol [5]. Alcoholism negatively affects addictive behaviors but anxious (stress and anxiety) and advanced cognitive behaviors (learning and memory) as well [6]. The behavioral, psychological and physiological mechanisms underlying the effect of alcohol on human neural physiological processes has remained elusive [7]

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Results

Conclusion