Water maze and radial maze learning and the density of binding sites of glutamate, GABA, and serotonin receptors in the hippocampus of inbred mouse strains

Correlations between the densities of ionotropic glutamate, GABA(A), and se rotonin binding sites in the hippocampus of seven inbred mouse strains and strain-specific learning capacities in two types of maze were studied. Bind ing site densities were measured with quantitative receptor autoradiography . Learning capacities were determined in a water maze task as well as in sp atial and nonspatial versions of an eight-arm radial maze. The densities of most binding sites differed significantly between the strains in the subfi elds of Ammon's horn (CA1 and CA3) and the dentate gyrus, except for seroto nin binding sites in CA1. By comparing the different strains, significant r eceptor-behavioral correlations between the densities of the GABA(A) recept ors and the activity-dependent behavior in the water maze as well as the sp atial learning in the radial maze were found. The densities of D,L-alpha-am ino-3-hydroxy-5-methyl-4-isoxalone propionate (AMPA) and kainate receptors correlated positively with learning capacity in the spatial eight-arm radia l maze. We conclude that hereditary variations mainly in AMPA, kainate, and GABA(A) receptor densities are involved in behavioral variations in spatia l and nonspatial learning tasks. (C) 2000 Wiley-Liss, Inc.