<；P>；PROBLEM TO BE SOLVED: To provide a null mutant non-human animal useful as a model animal of excessive salt intake experiments, and showing salt intake behavior similar to that of wild-type animals under water-sufficient conditions and much more intakes of hypertonic salt compared with wild type animals under water-depleted conditions, e.g., an Nav2 channel gene-deficient non-human animal. <；P>；SOLUTION: The Nav2 knockout mouse is prepared by screening mouse genomic DNA libraries with rat NaGcDNA as a probe, isolating Nav2 gene of genomic DNA, preparing a targeting vector by inserting marker gene such as neo gene into the exon of Nav2, introducing the prepared targeting vector into ES cells, selecting homologously recombined ES cells, preparing germ line chimeric mice by using the ES cells and mutually intercrossing heterozygous mutant mice having been prepared by hybridizing the chimeric mice with the wild type mice. <；P>；COPYRIGHT: (C)2011,JPO&INPIT
