Acoustic startle responses and prepulse inhibition of acoustic startle responses in Warsaw alcohol High-Preferring (WHP) and Warsaw Alcohol Low-Preferring (WLP) rats

Abstract

Aims: An assessment of the acoustic startle response (ASR) and prepulse inhibition (PPI) of ASR in laboratory animals is used to model human anxiety and psychotic states, respectively. The aim of the study was to evaluate ASR and PPI in alcohol-naive male and female Warsaw alcohol high-preferring (WHP) and Warsaw alcohol low-preferring (WLP) rats. Methods: ASR and PPI were assessed in two separate experiments by using the SR-LAB apparatus (San Diego Instruments, San Diego, CA, USA). In the ASR session, animals (n = 13-16 rats per group) were exposed to startling stimuli of different intensities (72, 84, 98, 112 and 124 dB) in a random order. In the PPI session, prepulse stimuli (78, 81, 84 and 90 dB) preceded a pulse startling stimulus (120 dB) in a random order. The background white noise was set at 70 dB. PPI was calculated according to the formula: [(startle amplitude in pulse alone trials-startle amplitude in prepulse-and-pulse trials)/startle amplitude in pulse alone trials] × 100%. Results: The WHP males exhibited higher startle amplitudes in response to 112 dB stimuli when compared with their WLP counterparts. The WHP females showed higher startle reactivity to 112 and 124 dB stimuli when compared with the WLP females. There were no differences between the WHPs and WLPs in PPI of ASR. Conclusion: The results of the present study suggest that exaggerated startle responses can be a physiological/behavioral marker of a propensity to abuse alcohol. © The Author 2012. Medical Council on Alcohol and Oxford University Press. All rights reserved.