The Fawn-hooded rat has long been used as a model for various peripheral and central
disorders and the data available indicate that the social behavior of this strain
may be compromised. However, a thorough description of the Fawn-hooded rat is unavailable
in this regard. The objective of the present study was to investigate various aspects
of the Fawn-hooded rat’s social behavior in depth. Our results show that several facets
of socio-communicational behavior are impaired in the RjIbm(m):FH strain, including
defective ultrasonic vocalizations in pups upon maternal deprivation, reduced social
play in adolescence and impaired social novelty discrimination in adulthood. In addition,
Fawn-hooded rats exhibited heightened tactile sensitivity and hyperactivity. The defects
observed were comparable to those induced by prenatal valproate exposure, a widely
utilized model of autism spectrum disorder. Further on, the pro-social drug R-baclofen
(0.25–1 mg/kg) reversed the autistic-like defects observed in Fawn-hooded rats, specifically
the deficiency in ultrasonic vocalization, tactile sensitivity and social novelty
discrimination endpoints. In conclusion, the asocial, hypersensitive and hyperactive
phenotype as well as the responsivity to R-baclofen indicate this variant of the Fawn-hooded
rat strain may serve as a model of autism spectrum disorder and could be useful in
the identification of novel drug candidates.
