Behavioral differences between two inbred strains of Fawn-Hooded rat: a model of serotonin dysfunction

The Fawn-Hooded rat (FH) strain has attracted the attention of some psychopharmacologists because of reports of its exaggerated immobility in the swim test, hypercortisolemia, excessive voluntary intake of alcohol, platelet and central serotonin abnormalities and subsensitivity to serotonergic agonists. However, there appears to be some controversy over several behavioral and physiological characteristics of these rats. The present paper proposes that the lack of reproducible findings can be traced to there being several distinct inbred strains of FH rats. Of the two compared in this communication, the FH/Wjd strain is more immobile in the forced swim test, spends more time in the open arms of the elevated plus maze, and drinks more saccharin and alcohol voluntarily than the FH/Har (Iowa Reactive) strain. Future workers are cautioned to report the source of their FH rats.