It takes a lot of time to produce homozygous mutant mice that are suitable for phenotyping.
To test their theory, the researchers studied normal mice and mutant mice that lack CB1.
Mutant mice that can't stop scratching themselves have led scientists to a gene--whimsically dubbed Itch--that helps control inflammation.
In a search for mutant mice that might be missing the gene, Banfi and colleagues came upon a strain called head slant.
To investigate, they took leptin-deficient mutant mice that grow five times as fat as normal mice do, then injected them with leptin.
To test whether the mast cells are responsible for lymph node swelling, Abraham and colleagues injected bacteria under the skin of mutant mice that have no mast cells.
In normal mice, ginkgo halved the volume of brain tissue injured after a stroke, but it had little effect on mutant mice that lacked heme oxygenase.
The in vivo actions of ITet were investigated by using mutant mice that express IL-2Rα in striatal neurons under the control of the gene encoding dopamine D2 receptor.
This transgenic line will allow the generation of conditional mutant mice that lack specific gene products along the serotonergic pathways and represents a unique tool for studying 5-HT1A-mediated serotonin signaling in the developing and adult brain.
It does not appear to be essential for that job, however, because the copious fat tissue in mutant mice that completely lack leptin manages to recruit an adequate blood supply.
This hunt gave a boost to another quest that had been under way for 2 years: finding the gene defect in mutant mice that show the same symptoms as Niemann-Pick patients.
