The single exon of the mouse Drd1a (dopamine receptor D1A) gene is flanked by loxP sites in this conditional targeted mutant strain. Cre-mediated excision of the floxed region produces a knockout allele.
Animals created from crosses with Camk2a-Cre mice (e.g. Stock No. 005359) to create knockouts in excitatory neurons of the mouse forebrain demonstrate significant fear memory deficits. Animals created from crosses with Pomc-Cre mice (e.g. Stock No. 010714) to create knockouts in the granule cells of the dentate gyrus also demonstrate significant fear memory deficits. They exhibit generalized fear between two similar, but different, contexts. Dentate gyrus c-Fos levels in a familiar home cage are higher in the mutant mice than in control wildtype mice. However, c-fos levels do not increase further upon exposure to a novel context or upon shock delivery as observed in control animals. Evidence suggests that this gene contributes to the formation of distinct contextual representations of novel environments.
Animals homozygous for widespread knockouts of Drd1a receptors are not viable after weaning (~3 weeks of age) unless food access is made easily available (e.g., food paste near animal bedding).
