Evaluation of protective role of benzodiazepine in noise stress induced activation of hypothalamo-pituitary adrenal axis in albino rats

ABSTRACT

Noise, whether pleasant or not, is ever present in nature. Not much work can be done without noise, in the industries, fish market, social gatherings; it is constantly in the background. Thought it seems harmless loud and or prolonged exposure to noise can cause health problems to the populace. Noise, as a recognized stressogenic factor, has been postulated to stimulate the HPA axis leading to the release of stress hormones. The present study was designed to assess the changes occurring in the level of stress hormones [ACTH and Corticosterone] in albino rats when acutely [24 hrs] exposed to loud noise with subsequent ameliorating effects of benzodiazepine [Valium/ Diazepam] which will given to the rats to alleviate the symptoms of stress. Prospective Experimental Study. This study was conducted in the Department of Anatomy, JPMC, Karachi from Jan 2006 to June 2008. Three groups of 10 rats labeled A, B and C serving as control [no noise], noise stress [24hrs] and noise stress [24hrs] with diazepam [5mg/kg] respectively. The groups B and C were exposed to white noise at 100 dB. At the end of study the animals were sacrificed and their mean plasma concentration of ACTH and corticosterone were measured. A highly significant increase in mean plasma concentration of ACTH [150.90 +/- 14.71 pg/ml] and corticosterone [5.72 +/- 5.75 pg/ml] and corticosterone [1.75 +/- 0.25 micro/dl] concentration of control animals. This increase was significantly ameliorated by pre treatment of diazepam. Our study shows the protective role of diazepam in stress induced by noise