Research Description

The Effects of Chronic Stress on an Animal Model of Self Injurious Behavior

Self injurious behavior (SIB) is a debilitating characteristic of many developmental and genetic disorders, such as autism and Lesch-Nyhan syndrome. Common forms of SIB include self-biting, head-banging, self-punching, and skin picking. The neurochemical basis of SIB is unknown although some treatments exist, many of those who self-injure do not respond to any of them.

The Devine lab has identified that rats repeatedly treated with the drug pemoline begin to self injure. The injury that these rats express closely resembles SIB in human populations in that it seems compulsive and is confined to specific areas. Validity for this animal model of SIB is also evidenced by individual differences in vulnerability to self injure in both the rat and human populations. Additionally, the drugs that have shown therapeutic benefits in human populations also protect rats from self injuring. In human populations, stress has been shown to exacerbate SIB. Therefore, I am currently exploring the effects of chronic stress on self injury in the rat model.

To produce chronic social stress, each rat is placed in a highly stressful environment in which a dominant male rat pins him. The rats are exposed to social defeat (SD), injected with pemoline, and their injuries are evaluated. Any rat that self-injures enough to break the skin will be immediately terminated, and the Institutional Animal Care and Use Committee has approved all aspects of this experiment. Preliminary evidence of the effects of neurological changes from SD shows that as in human populations, stress intensifies self injury.