Mice that are homozygous for the serotonin transporter targeted mutation (SERT
-/- or 5-HTT
-/-) are viable and fertile with a superficially unremarkable behavioral phenotype through early adulthood. Serotonin uptake is completely absent in homozygous mice. SERT-deficiency is pleiotropic (many different phenotypic traits). Homozygotes and, to a lesser extent, heterozygotes exhibit diminished responses to serotonin receptor agonists and other classes of drugs (including MDMA, SSRIs, 8-OH-DPAT, and DOI). SERT-mutant mice are also reported to have increased anxiety-like behaviors, altered neuroendocrine and sympathoadrenal responses to even minor stress, diminished aggression, altered emotional learning, substantially increased rapid eye movement (REM) sleep time, reduced brain excitability, increased body temperature, increased colonic motility, reduced spinal reflex to injury, reduced bladder response to stretching, blood pressure responses, diminished bone and muscle strength, reduced physical activity and exercise, and obesity associated with hyperglycemia and increased plasma levels of insulin, leptin, triglycerides and cholesterol. These SERT (or 5-HTT) mutant mice may be useful in studying the role of serotonin and serotonin transporter in behavior and learning, social anxiety, neuropsychiatric and neurological disorders (such as autism), pharmacological actions of therapeutic agents or drugs of abuse, inflammatory bowel disease, obesity and type 2 diabetes and other molecular consequences of SERT inactivation.
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. 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.