Intact LTP and Fear Memory but Impaired Spatial Memory in Mice Lacking Ca<SUB>v</SUB>2.3 (α<SUB>IE</SUB>) Channel

To investigate the functional roles of the Ca_v2.3 (α_1E) channel in hippocampal CA1 pyramidal neurons, we studied in vitro synaptic properties and in vivo behaviors of the Ca_v2.3 gene deficient mice. The Ca_v2.3 channel mRNA was identified in the hippocampal formation of the wild-type mouse by in situ hybridization. The basic excitatory synaptic transmission and long-term potentiation by theta-burst stimulation were intact in CA1 region of Ca_v2.3−/− mice. We performed two forms of behavioral tests to examine the hippocampus-dependent function, i.e., emotional and spatial learning tests. The Ca_v2.3−/− mice were able to establish and maintain fear memories. Although general improvement in the performance of Morris water maze test was seen in Ca_v2.3−/− mice, they displayed an obvious impairment in the probe test. These results suggest that the Ca_v2.3 channel plays some role in formation of the accurate spatial memory but not of the fear memory. Copyright 2001 Academic Press.