Behavioral consequences of the mGlu5 receptor antagonist MTEP in immature rats.

High doses of mGluR5 antagonists have anticonvulsant effects in multiple seizure models in both adult and immature animals. Data on potential behavioral effects in immature animals are very scarce. The present study investigated whether an antagonist of mGluR5 3-((2-methyl-1,3-thiazol-4-yl)ethynyl)pyridine (MTEP) in doses proven to be anticonvulsant affects behavior in immature rats. Animals aged 12, 18 and 25 days received MTEP in doses of 20 and 40 mg/kg i. p. The sensorimotor performance was tested at 15 and 60 min after dosing. Locomotor-exploratory behavior was tested at 20 and 65 min after dosing. An elevated plus maze was used to examine an adaptive form of learning and anxiety-like behavior in 18- and 25-day-old rats at 15, 60 min and 24h. MTEP slightly affected sensorimotor performance, regardless of age. In the open field test, MTEP decreased transiently locomotor-exploratory behavior but did not affect the habituation - a simple form of nonassociative learning. In the elevated plus maze, the drug did not impair transfer latency, an indicator of an adaptive form of learning and memory. An anxiolytic-like effect was observed at 60 min after drug administration. In conclusion, no severe impairment was observed after high anticonvulsant doses of mGlu5 antagonist MTEP in immature animals.