TIME-DEPENDENT QUANTIFIABLE WITHDRAWAL FROM ETHANOL IN THE RAT - EFFECT OF METHOD OF DEPENDENCE INDUCTION

The importance of temporal factors on the presence and severity of eth anol withdrawal signs in the rat was quantified using rating scale, tr emor, and acoustic startle paradigms. Ethanol dependence was induced i n naive male Wistar rats by liquid diet administration (n = 21) or vap or inhalation (n = 13). Subjects were analyzed for intensity and durat ion of physiological ethanol dependence in repeated-measures trials co nducted over 72 h post-ethanol withdrawal. Indices of dependence inclu ded CNS hyperexcitability manifested as observable withdrawal signs in creased acoustic startle reactivity, and tremor activity. Data analysi s revealed that withdrawal signs, observed and elicited, generally rea ched peak intensities between 12 and 24 h postwithdrawal and were more readily observed following vapor inhalation than liquid diet administ ration, probably because of the higher BALs attained with the inhalati on procedure. Results suggest a difference in time course observed wit h the different behavioral paradigms. In particular, a possible sensit ization to startle stimuli was exhibited independent of both startle i ntensity and dependence induction method. The neural substrates govern ing these behavioral time course differences remain to be determined.