A preliminary study of single prolonged stress influence acoustic startle reflex and prepulse inhibition in rats

Objective To explore the deficits of acoustic startle reflex (ASR) and prepulse inhibition (PPI) of acoustic startle reflex in single prolonged stress rats. Methods Sixty Sprague Dawley rats were randomly divided into control 1, 7, 14 d groups and stress 1, 7, 14 d groups.All stressed rats received single prolonged stress while all control rats were left in their home cage.Behavioral changes in these rats were analyzed in ASR and PPI paradigm. ASR and PPI were carried out on day 2, 8, 15, respectively. Results There were no differences of ASR and PPI among control 1, 7, 14 d groups (P>0.05). ASR of stress 1 d group((92.49±31.54)g) was higher than that of control 1 d group((64.48±17.95)g, P 0.05). Compared with control 7 d group((41.30±12.79)%), PPI in stress 7 d group((17.95±31.79)%) was reduced (P<0.05). Compared with control 14 d group ((41.16±12.25)%), PPI in stress 14 d group((13.71±32.48)%) was reduced (P<0.05). Conclusion Effects of stress on ASR in rats increased in early period, while the impaired PPI may last for a long time. Key words: Single prolonged stress; Acoustic startle reflex; Prepulse inhibition