Journal of Clinical & Experimental Pharmacology

Corticosterone mitigates the stress response in an animal model of PTSD

World Congress on Pharmacology

July 20-22, 2015 Brisbane, Australia

He Li

Posters-Accepted Abstracts: Clin Exp Pharmacol

Abstract:

Elevated startle response and hyperarousal are hallmarks of PTSD, and are generally considered to evince fear (DSM V). To further examine the efficacy of corticosterone in treating hyper arousal and elevated fear, the present study utilized a learned helplessness stress model in which rats are restrained and subjected to tail shock for three days. These stressed rats develop a delayed long-lasting exaggeration of the acoustic startle response (ASR) and retarded body weight growth, similar to symptoms of PTSD patients. We demonstrate that both pre-stress and post-stress administration of corticosterone mitigates a subsequent exaggeration of the ASR measured 14 days after cessation of the stress protocol. Furthermore, the mitigating efficacy of pre-stress administration of corticosterone (3 mg/kg/day for three days) appeared to last significantly longer, up to 21 days after the cessation of the stress protocol, in comparison to that of post-stress administration of corticosterone. However, pre-stress administration of corticosterone at 0.3 mg/kg/day for three days did not mitigate stress-induced exaggeration of the ASR measured at both 14 and 21days after the cessation of the stress protocol. In addition, pre-stress administration of corticosterone mitigates the retardation of body weight growth otherwise resulting fromthe stress protocol. The relative efficacy of pre versus post administration of corticosterone and high versus low dose of corticosterone on stress induced exaggeration of innate fear response and stress-retarded body weight growth indicate that exogenous corticosterone administration within an appropriate time window and dosage are efficacious in diminishing traumatic stress induced pathophysiological processes.