Elevated mazes as animal models of anxiety: effects of serotonergic agents

Simone H Pinheiro,Cristina M Del-Ben,Frederico G Graeff,Hélio Zangrossi-Jr

doi:10.1590/s0001-37652007000100010

Simone H Pinheiro, Cristina M Del-Ben + Show 2 more

Open Access

https://doi.org/10.1590/s0001-37652007000100010

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Abstract

This article reviews reported results about the effects of drugs that act upon the serotonergic neurotransmission measured in three elevated mazes that are animal models of anxiety. A bibliographic search has been performed in MEDLINE using different combinations of the key words X-maze, plus-maze, T-maze, serotonin and 5-HT, present in the title and/or the abstract, with no time limit. From the obtained abstracts, several publications were excluded on the basis of the following criteria: review articles that did not report original results, species other than the rat, intracerebral drug administration alone, genetically manipulated rats, and animals having any kind of experimental pathology. The reported results indicate that the effect of drugs on the inhibitory avoidance task performed in the elevated T-maze and on the spatio temporal indexes of anxiety measured in the X and plus mazes correlate with their effect in patients diagnosed with generalized anxiety disorder. In contrast, the drug effects on the one-way escape task in the elevated T-maze predict the drug response of panic disorder patients. Overall, the drug effects assessed with the avoidance task in the T-maze are more consistent than those measured through the anxiety indexes of the X and plus mazes. Therefore, the elevated T-maze is a promising animal model of generalized anxiety and panic disorder.

Highlights

Animal models of anxiety have been developed on the basis of paradigms taken from the experimental psychology of the 1950s and 60s, before the modern classification of psychiatric disorders had split anxiety disorders in different diagnostic categories
We compare the results reported in the literature describing the effects of such drugs on the behavioral indexes of anxiety and panic measured in the three above types of elevated mazes
To improve clarity of analysis, the reviewed results are divided into two sets; the first comprises results obtained with 5-HT reuptake inhibitors and the second, with drugs that act as agonists or antagonists on different subtypes of 5-HT receptors

Summary

Introduction

Animal models of anxiety have been developed on the basis of paradigms taken from the experimental psychology of the 1950s and 60s, before the modern classification of psychiatric disorders had split anxiety disorders in different diagnostic categories. As a consequence, these animal models refer to normal and pathological anxiety, in general. These animal models refer to normal and pathological anxiety, in general On the whole, they rely on either inhibition of ongoing behavior elicited by conditioned stimuli that predict unavoidable electric shock or on suppression of rewarded behavior by concurrent electric-shock. Punishment tests have been criticized because of their artificiality and the confounding influence of appetitive drives, such as hunger and thirst, as well as of pain (Treit 1985)

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