Mice homozygous for this delta-opioid receptor mutant allele (DOR-) are viable and fertile. DOR-selective ligand binding is absent in vitro on brain membranes from homozygous mice. Unlike mutant mice deficient in kappa- or mu-opioid receptors (Stock No. 007558 or 007559, respectively), homozygous DOR- mutants exhibit increased anxiety and depressive-like behavior but no alteration of spontaneous pain perception. Homozygous DOR- mice also have increased ethanol self-administration and increased inflammatory pain. These DOR mutant mice may be useful in studying the biological activity of opioids andanalgesics, mechanical nociception, inflammatory pain, and emotional disorders.
In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. These mutant mice were originally published on a mixed genetic background, and the donating investigator reports that increased anxiety may not be observable on this congenic background. It should be noted that the phenotype could vary from that originally described. We will modify the strain description if necessary as published results become available.
