Loud noise exposure induces associative memory and anxiety levels impairments

URAN S. L.; CACERES L.G.; GUELMAN L.R.

Congreso; II Reunión Conjunta de Neurociencias (IRCN); 2010

Living organisms are continuously exposed to potentially hazardous noise levels coming from the environment that might produce extra-auditory effects, including behavioral alterations. The aim of the present work was to test if loud noise exposure can affect associative memory and anxiety.Male Wistar rats of 15 days were exposed to white noise (95-97dB, 2h/day) and separated into 2 groups, acute (AE, 2h/day) and chronic exposure (CE, 2h/day for 15 d).Passive avoidance test (PA) was used to evaluate the associative memory whereas open field (OF) and elevated plus maze (EPM) was used as anxiety-related tests in 30-days-old rats. PA and OF were performed at short (1 h, ST) and long-term (24 h, LT).Results showed an impairment in PA test in exposed CE animals, with a decreased latency to enter the dark compartment, both at ST and LT (rate T2/T1, ST: AE, NS; CE, p<0.05; LT: AE, NS; CE, p<0.01). On the other hand, OF and EPM results show a decrease in anxiety level in CE exposed rats. Latency to enter the centre when the animals were first place in the OF was decreased in CE, both at ST and LT (ST: AE, NS; CE, p<0.05; LT: AE, NS; CE, p<0.01). Similarly, the number of entries (E) as well as the total time (%T) spent on open arms in EPM were increased (E: AE, NS; CE, p<0.05; %T: AE, NS; CE, p<0.05).These results suggest that CE to loud noise can induce associative memory impairments and anxiety-related changes, supporting the high vulnerability of developing rodents to stressors such as noise exposure.