scholarly journals Infralimbic cortex controls fear memory generalization and susceptibility to extinction during consolidation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hugo Bayer ◽  
Leandro Jose Bertoglio
Keyword(s):  
Protein Synthesis ◽  
Elevated Plus Maze ◽  
Fear Memory ◽  
Contextual Fear Conditioning ◽  
Protein Synthesis Inhibition ◽  
Infralimbic Cortex ◽  
Contextual Fear ◽  
Memory Specificity ◽  
Elevated Plus Maze Test ◽  
Plus Maze

Abstract Lesioning or inactivating the infralimbic (IL) subregion of the medial prefrontal cortex before acquisition produces more generalized and extinction-resistant fear memories. However, whether and how it modulates memory specificity and extinction susceptibility while consolidation takes place is still unknown. The present study aims to investigate these questions using muscimol-induced temporary inactivation and anisomycin-induced protein synthesis inhibition in the rat IL following contextual fear conditioning. Results indicate that the IL activity immediately after acquisition, but not six hours later, controls memory generalization over a week, regardless of its strength. Such IL function depends on the context-shock pairing since muscimol induced no changes in animals exposed to immediate shocks or the conditioning context only. Animals in which the IL was inactivated during consolidation extinguished similarly to controls within the session but were unable to recall the extinction memory the following day. Noteworthy, these post-acquisition IL inactivation-induced effects were not associated with changes in anxiety, as assessed in the elevated plus-maze test. Anisomycin results indicate that the IL protein synthesis during consolidation contributes more to producing extinction-sensitive fear memories than memory specificity. Collectively, present results provide evidence for the IL's role in controlling generalization and susceptibility to extinction during fear memory consolidation.

Anticonvulsant, Anxiolytic and Antidepressant Properties of the β-caryophyllene in Swiss Mice: Involvement of Benzodiazepine-GABAAergic, Serotonergic and Nitrergic Systems

2020 ◽  
Vol 14 (1) ◽  
pp. 36-51 ◽  
Author(s):  
George L. da Silva Oliveira ◽  
José C. Correia L. da Silva ◽  
Ana P. dos Santos C. L da Silva ◽  
Chistiane M. Feitosa ◽  
Fernanda R. de Castro Almeida
Keyword(s):  
Receptor Antagonist ◽  
Molecular Mechanisms ◽  
Elevated Plus Maze ◽  
Feeding Test ◽  
Swiss Mice ◽  
Elevated Plus Maze Test ◽  
Maze Test ◽  
Plus Maze ◽  
Gabaergic Receptors ◽  
Pre Treatment

Background: Central nervous system disorders such as anxiety, depression and epilepsy are characterized by sharing several molecular mechanisms in common and the involvement of the L-arginine/NO pathway in neurobehavioral studies with β-caryophyllene is still little discussed. Objectives: One of the objectives of the present study was to demonstrate the anxiolytic behavioral effect of β-caryophyllene (β-CBP) in female Swiss mice, as well as to investigate the molecular mechanisms underlying the results obtained. Methods: This study evaluated the neurobehavioral effects of β-CBP using the open field test, rota-rod test, elevated plus maze test, novelty suppressed feeding test, tail suspension test and forced swim test, as well as pilocarpine, pentylenetetrazole and isoniazid-induced epileptic seizure models. Results:: The results demonstrated that the neuropharmacological activities of β-CBP may involve benzodiazepine/GABAergic receptors, since the pre-treatment of β-CBP (200 mg/kg) associated with flumazenil (5 mg/kg, benzodiazepine receptor antagonist) and bicuculline (1 mg/kg, selective GABAA receptor antagonist) reestablished the anxiety parameters in the elevated plus-maze test, as well as the results of reduced latency to consume food in the novelty suppressed feeding test. In addition to benzodiazepine/GABAergic receptors, the neuropharmacological properties of β-CBP may be related to inhibition of nitric oxide synthesis, since pre-treatment with L-arginine (500- 750 mg/kg) reversed significantly the anxiolytic, antidepressant and anticonvulsant activities of β-CBP. Conclusion: The results obtained provide additional support in understanding the neuromolecular mechanisms underlying the anxiolytic, antidepressant and anticonvulsive properties of β-CBP in female Swiss mice.

scholarly journals Effects of test experience, closed-arm wall color, and illumination level on behavior and plasma corticosterone response in an elevated plus maze in male C57BL/6J mice: a challenge against conventional interpretation of the test

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Hirotaka Shoji ◽  
Tsuyoshi Miyakawa
Keyword(s):  
Elevated Plus Maze ◽  
Plasma Corticosterone ◽  
Illumination Level ◽  
Test Battery ◽  
Lower Percentage ◽  
Behavioral Tests ◽  
Elevated Plus Maze Test ◽  
Maze Test ◽  
Plus Maze ◽  
Corticosterone Response

AbstractThe elevated plus maze test is a widely used test for assessing anxiety-like behavior and screening novel therapeutic agents in rodents. Previous studies have shown that a variety of internal factors and procedural variables can influence elevated plus maze behavior. Although some studies have suggested a link between behavior and plasma corticosterone levels, the relationships between them remain unclear. In this study, we investigated the effects of experience with a battery of behavioral tests, the wall color of the closed arms, and illumination level on the behavior and plasma corticosterone responses in the elevated plus maze in male C57BL/6J mice. Mice were either subjected to a series of behavioral tests, including assessments of general health and neurological function, a light/dark transition test, and an open field test, or left undisturbed until the start of the elevated plus maze test. The mice with and without test battery experience were allowed to freely explore the elevated plus maze. The other two independent groups of naïve mice were tested in mazes with closed arms with different wall colors (clear, transparent blue, white, and black) or different illumination levels (5, 100, and 800 lx). Immediately after the test, blood was collected to measure plasma corticosterone concentrations. Mice with test battery experience showed a lower percentage of open arm time and entries and, somewhat paradoxically, had lower plasma corticosterone levels than the mice with no test battery experience. Mice tested in the maze with closed arms with clear walls exhibited higher open arm exploration than mice tested in the maze with closed arms with black walls, while there were no significant differences in plasma corticosterone levels between the different wall color conditions. Illumination levels had no significant effects on any measure. Our results indicate that experience with other behavioral tests and different physical features of the maze affect elevated plus maze behaviors. Increased open arm time and entries are conventionally interpreted as decreased anxiety-like behavior, while other possible interpretations are considered: open arm exploration may reflect heightened anxiety and panic-like reaction to a novel situation under certain conditions. With the possibility of different interpretations, the present findings highlight the need to carefully consider the test conditions in designing experiments and drawing conclusions from the behavioral outcomes in the elevated plus maze test in C57BL/6J mice.

Anxiety levels and wild running susceptibility in rats: assessment with elevated plus maze test and predator odor exposure

2005 ◽  
Vol 68 (2) ◽  
pp. 135-144 ◽  
Author(s):  
Hugo Medeiros Garrido de Paula ◽  
Amauri Gouveia ◽  
Marcos Vinícius de Almeida ◽  
Katsumasa Hoshino
Keyword(s):  
Elevated Plus Maze ◽  
Predator Odor ◽  
Elevated Plus Maze Test ◽  
Maze Test ◽  
Plus Maze ◽  
Anxiety Levels ◽  
Odor Exposure

Neuropharmacological Activity of Various Fractions Obtained from Solanum aethiopicum (Linn.) Fruit in Mice.

2020 ◽  
Vol 1 (5) ◽  
pp. 12-23
Author(s):  
A.R. Abubakar ◽  
◽  
I.H. Sani ◽  
S. Malami ◽  
A.H. Yaro ◽  
...  
Keyword(s):  
Open Field ◽  
Elevated Plus Maze ◽  
Toxicity Testing ◽  
Aqueous Fraction ◽  
Solanum Aethiopicum ◽  
Elevated Plus Maze Test ◽  
Board Test ◽  
Plus Maze ◽  
Hole Board ◽  
Hole Board Test

Background: Solanum aethiopicum (L.), family Solanaceae, is known as garden eggs. The fruit is used in the treatment of insomnia, diabetes and constipation. Objective: The aim of this study was to evaluate anxiolytic-like activity of fractions obtained from crude methanol extract of Solanum aethiopicum fruit. Method: Acute toxicity testing was conducted according to the OECD guidelines 420 via oral and intraperitoneal routes (ip). n-Hexane (HF), chloroform (CHF), ethyl-acetate (EAF), n-butanol (BF) and residual aqueous fraction (RAF) at doses of 25, 50 and 100 mg/kg ip were experimented using the open field, elevated plus maze, staircase, light dark box and hole-board tests. Results: Results: In open field test, there was statistically significant increase in frequency of central square entry by EAF 25mg/kg, 50mg/kg and 100mg/kg and RAF 25mg/kg, 50mg/kg and 100mg/kg all at p<0.05 compared to distilled water (D/W) group. Elevated plus maze test showed statistically significant increases in open arm entry and duration by CHF 25mg/kg, RAF 25mg/kg and 50mg/kg again at p<0.05. Also, in the staircase test, statistically significant decrease in frequency of rearing with no effect on step climbing was observed by RAF 25mg/kg (p< 0.05) compared to D/W. Light and dark box test produced increased light box entry and duration by EAF 25mg/kg, RAF 25mg/kg and 50mg/ kg at p<0.05. Furthermore, the hole -board test showed statistically significant increases in number of head dips by EAF 50mg/kg and 100mg/kg as well as RAF 25mg/kg, 50mg/kg and 100 mg/kg at p<0.05. Conclusion: The fractions obtained from Solanum aethiopicum fruits possesses anxiolytic-like activity.

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