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Effect of MPEP on rat's behavioral activity in experimental episodes of hypoxia
1Department of Pharmacology, Medical University of Białystok, Białystok, Poland.
Purpose:
The influence of the selective antagonism of metabotropic glutamate receptor subtype 5 (mGluR5) by MPEP (2-methyl-6-(phenylethynyl)-pyridine) on some behaviors was tested in control groups of rats and in rats exposed to short-term hypoxia once or to repeated episodes of hypoxia.
Material And Methods:
We used the following methods: the open field test, the passive avoidance test and the object recognition test. Experimental hypoxia was produced by placing rats in a glass chamber flushed with a mixture of 2% O2 in N2.
Results:
MPEP applied intravenously (IV) at the dose of 1 mg kg-1 significantly enhanced locomotor and exploratory activity, impaired acquisition, but improved consolidation and retrieval in the passive avoidance situation and did not alter rats' activity in the object recognition test. The single short-term hypoxia significantly inhibited motility of rats and profoundly impaired acquisition, consolidation and retrieval processes, but the positive effect of MPEP on retrieval was preserved. Hypoxia also did not influence the activity of rats in the object recognition object. The repeated episodes of short-term hypoxia were induced for five consecutive days and it also inhibited motility of rats, but did not change consolidation and retrieval processes. The episodes of hypoxia significantly diminished the beneficial effect of MPEP on consolidation and retrieval, and also the enhancement of locomotor and exploratory activity. MPEP, used in rats subjected to the single or the repeated episodes of short-term hypoxia, did not change recognition memory.
Conclusion:
MPEP used before the single episode of hypoxia only, had beneficial effect on retrieval.
Insights
Metabotropic glutamate receptor 5 (mGluR5) antagonism with MPEP benefits memory retrieval after single hypoxia events in rats. However, repeated hypoxia diminishes MPEP
Area of Science:
- Neuroscience
- Pharmacology
Background:
- Metabotropic glutamate receptor subtype 5 (mGluR5) plays a role in synaptic plasticity and cognitive functions.
- Hypoxia, a condition of oxygen deprivation, can impair cognitive processes, including memory.
- MPEP is a selective antagonist of mGluR5.
Purpose of the Study:
- To investigate the effects of MPEP, a selective mGluR5 antagonist, on behaviors in rats under normal conditions and following short-term or repeated hypoxia.
- To determine if MPEP can mitigate cognitive deficits induced by hypoxia.
Main Methods:
- Rats were subjected to single or repeated short-term hypoxia (2% O2 in N2).
- Behavioral tests included open field, passive avoidance, and object recognition.
- MPEP was administered intravenously (IV) at a dose of 1 mg/kg.
Main Results:
- MPEP enhanced locomotor activity and improved memory consolidation and retrieval in the passive avoidance test in control rats.
- Single hypoxia impaired all phases of passive avoidance memory, but MPEP preserved retrieval benefits.
- Repeated hypoxia reduced motility and diminished MPEP's beneficial effects on memory and activity, while recognition memory remained unaffected by MPEP in hypoxic rats.
Conclusions:
- MPEP demonstrates a beneficial effect on memory retrieval when administered before a single hypoxic episode.
- Repeated hypoxia exposure significantly attenuates the positive effects of MPEP on memory consolidation, retrieval, and locomotor activity.
