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Subchronic treatment increases the duration of the cognitive enhancement induced by metrifonate
M Riekkinen1, B H Schmidt, P Riekkinen
1Department of Neuroscience and Neurology, University of Kuopio and Kuopio University Hospital, Finland.
Abstract:
The study compared the efficacy of acute versus chronic metrifonate treatment to improve initial and reversal learning of the water maze spatial navigation task in medial septal-lesioned rats. Acute oral administration of 30 mg/kg metrifonate at 30 min, but not at 150 or 360 min, before training improved the initial acquisition of the water maze task. In contrast, improvement of initial learning performance of medial septal-lesioned rats pretreated for 21 days with metrifonate was observed irrespective of the timing of metrifonate treatment relative to behavioral testing. Reversal learning was assessed after a four-day wash-out period. No drug treatment was administered during this part of the study. All the medial septal-lesioned rats that had received only acute treatment with metrifonate during the initial learning stage were now as impaired as vehicle treated medial septal-lesioned rats. However, the group subchronically pretreated with metrifonate performed better than the vehicle-treated medial septal-lesioned controls. These results indicate that both acute and subchronic treatment with metrifonate can facilitate spatial learning in medial septal-lesioned rats and the transient nature of this beneficial effect after single acute administration is transformed into a long-lasting improvement by subchronic treatment.
Insights
Acute or chronic metrifonate treatment improved spatial learning in rats with medial septal lesions. Chronic treatment provided lasting benefits for water maze performance, unlike acute administration.
Area of Science:
- Neuroscience
- Pharmacology
- Behavioral Science
Background:
- Medial septal lesions impair spatial navigation in rats.
- Metrifonate is an acetylcholinesterase inhibitor with potential cognitive-enhancing effects.
Purpose of the Study:
- To compare the efficacy of acute versus chronic metrifonate treatment on spatial learning and memory in rats with medial septal lesions.
- To investigate the duration of metrifonate's effects on water maze performance.
Main Methods:
- Rats with medial septal lesions were treated acutely or chronically with metrifonate.
- Spatial learning was assessed using the water maze task, including initial acquisition and reversal learning.
- A washout period was implemented before assessing reversal learning to evaluate the persistence of treatment effects.
Main Results:
- Acute metrifonate administration (30 mg/kg) 30 minutes before training improved initial water maze acquisition.
- Chronic (21-day) metrifonate pretreatment improved initial learning regardless of treatment timing.
- While acute metrifonate's benefits were transient, subchronic treatment led to sustained improvement in reversal learning compared to controls.
Conclusions:
- Both acute and subchronic metrifonate administration can enhance spatial learning in medial septal-lesioned rats.
- Subchronic metrifonate treatment transforms the transient benefits of acute administration into long-lasting improvements in spatial memory.