Effect of enriched environment on Ca2+ uptake via NMDA receptors into barrel cortex slices of spontaneously hypertensive rats.

Abstract

Exposure to an enriched environment provides animals with informal learning opportunities and is associated with increases in brain size, cortical thickness, neuron size, dendritic branching, spine density, and number of synapses per neuron. The NMDA receptor is involved in synaptic plasticity. This study sought to determine the effect of exposure to an enriched environment on NMDA receptor function in barrel cortex slices of spontaneously hypertensive rats (SHR) and their control Wistar-Kyoto (WKY) rats. An assortment of items such as PVC pipes, metal pipes, metal boxes, metal ladders, and a polystyrene maze, were placed successively in the cages of test animals to create an enriched environment. After 2 weeks, the rats were killed. Their brains were rapidly removed, cooled in continuously oxygenated HEPES buffer (pH 7.4), and sliced in a vibratome to produce 0.35-mm thick slices. The barrel cortex was dissected from slices corresponding to 8.6-4.8 mm anterior to the interaural line and incubated with 45Ca2+ and 100 microM NMDA for 2 min. There was no difference between rats exposed to an enriched environment and rats kept in standard cages. Enrichment of environment did not alter NMDA-stimulated Ca2+ uptake into barrel cortex of SHR and WKY.