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Temporal analysis of the rat's behavior in the plus-maze: effect of midazolam
V P Rosa1, N Vandresen, A V Calixto
1Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina, 88.040-900, SC, Florianópolis, Brazil.
Abstract:
The aim of the present study was to carry out a temporal analysis of the midazolam (MDZ)-induced anxiolysis in rats submitted to the elevated plus-maze (EPM) test. Male Wistar rats received either MDZ (0.5, 1.0 and 1.5 mg.kg(-1)) or saline (0.9%) and were submitted to the EPM test. Temporal analysis revealed that the group receiving MDZ (1.5 mg.kg(-1)), as well as the group treated with saline, displayed low %Open arm entries, which suggests increased anxiety over the test period. Motor activity, evaluated by the enclosed arm entries, was also decreased in both experimental groups, thus suggesting locomotor habituation. The treatment with MDZ (1.5 mg. kg(-1)) induced a clear anxiolysis during the first 3 min, but not at the end of the test, since only the %Open arm time remained increased. The data are discussed with reference to the lack of the test's sensitivity to alterations in the level of anxiety over time and with respect to a qualitative shift in the experimental anxiety at the end of the session.
Insights
Midazolam (MDZ) showed anxiolytic effects in rats within the first 3 minutes of the elevated plus-maze test. However, sustained anxiety reduction was not observed, indicating potential limitations in assessing anxiety over time.
Area of Science:
- Neuroscience
- Pharmacology
- Behavioral Science
Background:
- Anxiety disorders are prevalent, necessitating effective therapeutic agents.
- Midazolam (MDZ) is a benzodiazepine with known anxiolytic properties.
- The elevated plus-maze (EPM) is a standard behavioral test for assessing anxiety in rodents.
Purpose of the Study:
- To conduct a temporal analysis of midazolam (MDZ)-induced anxiolysis in rats using the elevated plus-maze (EPM) test.
- To investigate the time-dependent effects of MDZ on anxiety-related behaviors.
- To evaluate the sensitivity of the EPM test to temporal changes in anxiety.
Main Methods:
- Male Wistar rats were administered varying doses of MDZ (0.5, 1.0, 1.5 mg.kg(-1)) or saline.
- Rats were subjected to the elevated plus-maze (EPM) test to assess anxiety and motor activity.
- Temporal analysis of behavioral parameters, including open arm entries and time spent in open arms, was performed.
Main Results:
- Midazolam (1.5 mg.kg(-1)) demonstrated anxiolysis during the initial 3 minutes of the EPM test.
- Both MDZ (1.5 mg.kg(-1)) and saline groups showed decreased open arm entries, suggesting anxiety.
- Motor activity, indicated by enclosed arm entries, decreased in both groups, suggesting habituation.
Conclusions:
- Midazolam exhibits transient anxiolytic effects in the EPM test.
- The EPM test may have limitations in detecting sustained anxiety changes over extended periods.
- A qualitative shift in experimental anxiety may occur towards the end of the session.