Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 48 2 2010 04 15 77 82 EN Azam Moslehi Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Fatemeh Nabavizadeh-Rafsanjani Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Mansoor Keshavarz Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Nematollah Rouhbakhsh Department of Audiology, Tehran University of Medical Sciences, Tehran, Iran. Masoud Sotudeh Department of Pathology, Shariati Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Ehsan Salimi Department of Pharmacy, Pharmacy School, Tehran University of Medical Sciences, Tehran, Iran. 2015 09 28 Noise is considered as one of the most severe sources of environmental and work place constraints. Noise effects on immune function, hormonal levels, cardiovascular and respiratory systems are well known. The aim of the study is to evaluate the effects of traffic noise on basal and stimulated gastric acid secretion. 48 healthy rats were divided into five traffic noise exposures (1, 7, 14, 21, 28 days) and a control groups. Pentagastrin was used IP for stimulation of gastric acid secretion. The gastric contents were collected by the wash-out technique and then titrated. Histological studies were performed on gastric epithelial layer. In the 1, 7, 14 and 21 days traffic noise exposure, basal and pentagastrin-stimulated gastric acid secretion increased compared to the control group (P<0.001), but a significant decrease was seen in hyperacidity in 28th days, in the both basal and stimulated states(P<0.05). Histological study showed that mucosal layer thickness of stomach increased, while the number of oxyntic glands and cell nuclei decreased. It seems that 1,7,14 and 21 days traffic noise increase gastric acid secretion, while 28 days traffic noise can induce adaptation. https://acta.tums.ac.ir/index.php/acta/article/view/3653 https://acta.tums.ac.ir/index.php/acta/article/download/3653/3628