Heritability of symptoms in the neuroma model of neuropathic pain: replication and complementation analysis.

Applying genetic selection pressure to an outbred population of albino rats, we have derived lines that show consistently high versus low pain phenotype in the neuroma model of neuropathic pain. Trait segregation developed rapidly, replicating earlier observations using this methodology. The resulting novel selection lines, designated nHA and nLA, share a common genetic background but have dramatically contrasting neuropathic pain behavior. In addition to confirming that the pain trait selected is heritable (estimated realized heritability h(2)=0.31), we have refreshed the availability of this research resource, namely animals of uniform genetic background but with contrasting pain phenotype. Crossing nHA rats with animals of the high (recessive) line from the earlier selection program (HA) yielded offspring almost uniformly high in pain phenotype. This complementation analysis indicates that the same gene(s) was selected in both selection programs, attesting to its unique salience in determining pain phenotype in the neuroma model.