Evaluation of Protective Role of Benzodiazepine in Noise Stress Induced Activation of Hypothalamo-Pituitary Adrenal Axis in Albino Rats

Abstract

Background: 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. Though 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. 
Aims & Objectives: The present study was designed to assess the changes occurring in the level of stress hormones 
(ACTH & 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. 
Study Design: Prospective Experimental Study.  
Place and Duration of Study: This study was conducted in the Department of Anatomy, JPMC, Karachi from Jan 
2006 to June 2008.  
Material and Methods: 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 & C were exposed to white 
noise at 100dB. At the end of study the animals were sacrificed and their mean plasma concentration of ACTH and 
corticosterone were measured. 
Results: A highly significant increase in mean plasma concentration of ACTH (150.90±14.71pg/ml) & 
corticosterone (5.72±0.28µg/dl) was observed in noise stressed group when compared with plasma ACTH 
(53.80±5.75pg/ml) & corticosterone (1.75±0.25µg/dl) concentration of control animals. This increase was 
significantly ameliorated by pre treatment of diazepam. 
Conclusion: Our study shows the protective role of diazepam in stress induced by noise.