Environmental enrichment and neurotransmitter receptors

The extent of high affinity, specific binding of several pharmacological agents to brain membrane fractions derived from rats reared in an environmentally enriched or impoverished environment has been assayed. The binding of all labeled agents studied was not significantly altered in cerebellar, subcortical, or cortical membranes by the rearing condition. In the case of cortical membranes, binding of 3H-benzodiazepine, 3H-dihydroalprenolol, 3H-dihydroergocryptine, 3H-spiroperidol, 3H-quinuclidinyl benzilate (QNB), and 3H-muscimol was not detectably altered by exposure to these two housing conditions. These data suggest that the observed small but statistically significant increase in density of cortical synapses in rats kept in the “enriched” condition may not necessarily reflect a great increase in a specific class of synapse.