Abstract
Studies have shown the ability of benzodiazepine drugs to cause memory loss in
animals and humans. Midazolam is a benzodiazepine commonly administered
intravenously during surgical procedures because it reacts rapidly, causes
anterograde amnesia, and has few side effects. It has also been used in
palliative medicine where, among others, an oral route has been employed for
chronic administration of the drug. The current study evaluated the effects of
chronic orally administered midazolam on spatial working memory and procedural
memory in control and experimental female rats over a three-week experimental
period utilizing the Morris water maze. Sample and test run times to a submerged
platform in the maze were recorded daily. In addition, activity wheels attached
to each cage were employed to monitor daily circadian activity of the animals.
Spatial working memory was not impaired in either group. However, procedural
memory amnesia occurred in animals receiving the drug indicative of a
consolidation or retrieval problem. Concerning circadian rhythms, a phase-shift
was noted in experimental animals possibly indicating that time of day of drug
administration is important. The findings of the present study could shed
insight into altered reactions observed in humans who have received midazolam as
a component of treatment in palliative medicine.
Key words
Morris water maze - amnesia - spatial working memory - procedural memory - palliative
- treatment
