Relating acoustic startle reactivity and plasticity to alcohol consumptionin male Wistar rats

The purpose of this study was to investigate the relationship between the s tartle response and ethanol. Aspects of the startle response, including ini tial and average startle, habituation, and prepulse inhibition (PPI) were s tudied. The startle response was measured to detect potential predictors of voluntary ethanol consumption and to observe whether ethanol ingestion wou ld affect startle in subsequent tests. Rats were tested three times in a st andard startle chamber. After the initial startle test, rats categorized as showing high or low PPI were allocated in a balanced way to a free-choice ethanol-water regime or to the water-regime control group. At the end of th e ethanol period (lasting for 16 days, including access to ethanol for 10 d ays), the rats were tested again in the startle chamber 24 h after ethanol removal. After 5 weeks of ethanol abstinence, rats were exposed to a final startle test. The response to the first 120-dB stimulus showed an inverted U-shaped. curvilinear relationship to later ethanol consumption. Startle ha bituation appeared to have predictive value regarding ethanol consumption, with rats showing the most efficient habituation drinking most. Data showed no relationship between PPI and ethanol intake. Rats given access to ethan ol showed greater habituation in the post-ethanol test than did the water c ontrols. After 5 weeks of abstinence. low ethanol-consuming rats showed low er startle responses to the first 120-dB stimulus than did high ethanol-con suming rats. The present data suggest a two-way relationship between startl e response characteristics and alcohol. (C) 2000 Elsevier Science Inc. All rights reserved.