Differences in stress-induced modulation of the auditory system between Wistar and Lewis rats

Many aspects of stress-induced physiological and psychological effects have been characterized in people and animals. However, stress effects on the auditory system are less explored and their mechanisms are not well-understood, in spite of its relevance for a variety of diseases, including tinnitus. To expedite further research of stress-induced changes in the auditory system, here we compare the reactions to stress among Wistar and Lewis rats. The animals were stressed for 24 h, and subsequently we tested the functionality of the outer hair cells (OHCs) using distortion product otoacoustic emissions (DPOAEs) and auditory neurons using evoked auditory brainstem responses (ABR). Lastly, using Western blot, we analyzed the levels of plasticity-related proteins in the inferior colliculus, confirming that the inferior colliculus is involved in the adaptive changes that occur in the auditory system upon stress exposure. Surprisingly, the two strains reacted to stress quite differently: Lewis rats displayed a lowering of their auditory threshold, whereas it was increased in Wistar rats. These functional differences were seen in OHCs of the apical region (low frequencies) and in the auditory neurons (across several frequencies) from day 1 until 2 weeks after the experimental stress ended. Wistar and Lewis rats may thus provide models for auditory threshold increase and decrease, respectively, which can both be observed in different patients in response to stress

Differences in Stress-Induced Modulation of the Auditory System Between Wistar and Lewis Rats

Many aspects of stress-induced physiological and psychological effects have been characterized in people and animals. However, stress effects on the auditory system are less explored and their mechanisms are not well-understood, in spite of its relevance for a variety of diseases, including tinnitus. To expedite further research of stress-induced changes in the auditory system, here we compare the reactions to stress among Wistar and Lewis rats. The animals were stressed for 24 h, and subsequently we tested the functionality of the outer hair cells (OHCs) using distortion product otoacoustic emissions (DPOAEs) and auditory neurons using evoked auditory brainstem responses (ABR). Lastly, using Western blot, we analyzed the levels of plasticity-related proteins in the inferior colliculus, confirming that the inferior colliculus is involved in the adaptive changes that occur in the auditory system upon stress exposure. Surprisingly, the two strains reacted to stress quite differently: Lewis rats displayed a lowering of their auditory threshold, whereas it was increased in Wistar rats. These functional differences were seen in OHCs of the apical region (low frequencies) and in the auditory neurons (across several frequencies) from day 1 until 2 weeks after the experimental stress ended. Wistar and Lewis rats may thus provide models for auditory threshold increase and decrease, respectively, which can both be observed in different patients in response to stress

Combined inhibition of Cdk5 and ROCK additively increase cell survival, but not the regenerative response in regenerating retinal ganglion cells

CNS regeneration is limited by lesion-induced neuronal apoptosis and an environment inhibiting axonal elongation. Inhibition of ROCK has been previously shown to promote regeneration in retinal ganglion cells (RGC) whereas Cdk5 inhibition mainly promoted survival. Therefore, we have evaluated the effects of combined treatment with inhibitors of ROCK and Cdk5. We show that in vitro, the co-application of the Cdk5 inhibitor, Indolinone A, and the ROCK inhibitor, Y-27632, potentiated the survival-promoting effect of either substance alone. However, neurite outgrowth in vitro was promoted only by the presence of Y-27632, not by Indolinone A alone. In the ex vivo explant and the in vivo optic nerve crush model the combination of both inhibitors significantly increased neurite outgrowth at small distances, but this effect leveled off for longer neurites. In Summary, the combined treatment with the Cdk5 inhibitor Indolinone A and the ROCK inhibitor Y-27632 results in a strong additive effect on neuronal survival, but is not able to increase the regenerative response beyond the effect of the ROCK inhibitor. (C) 2009 Elsevier Inc. All rights reserved

Attachment in toddlers with autism and other developmental disorders.

Contains fulltext : 52066.pdf (publisher's version ) (Closed access)Attachment was assessed in toddlers with Autistic Disorder (n=20), Pervasive Developmental Disorder (n=14), Mental Retardation (n=12), Language Development Disorder (n=16), and a non-clinical comparison group (n=18), using the Strange Situation Procedure (SSP). Children in the clinical groups were more often disorganized and less often securely attached. Severity of autism was associated with more attachment insecurity, and lower developmental level increased the chance for disorganized attachment. Attachment disorganization was related to increased heart rate during the SSP. Controlling for basal cortisol and developmental level, more autistic symptoms predicted lower cortisol responses to the SSP. The findings support the importance of disorganized attachment for children with autism