Acquisition and reversal of taste/tactile discrimination after forebrain noradrenaline depletion.

Assessed the role of noradrenaline (NA) on the acquisition of an aversively motivated discrimination task and its reversal. A conditioned taste aversion procedure was used. NA depletions were achieved through 2 pharmacological means: systemic N-2 chloroethyl-N-ethyl-2-bromo-benzylamine (DSP4) and destruction of the dorsal noradrenergic bundle (DNAB) with 6-hydroxydopamine (6-OHDA). Both procedures caused marked reductions of NA in the frontal cortex and hippocampus. In neither of the studies (Exp 1, DSP4 and Exp 2, DNAB) were there any significant changes between controls and NA-depleted rats in either the rate of acquisition of the original discrimination (Phase 1) or the subsequent reversal (Phase 2). This occurred irrespective of which of the 2 stimuli (a taste cue or a tongue-tactile cue) initially was used as the conditioned stimulus/stimuli (CS) (the stimulus first followed by contingent administration of lithium chloride and later, by saline injections). Thus NA does not appear to be critically involved in the acquisition and reversal of a taste/tactile discrimination task. The significance of forebrain NA for other discrimination tasks is discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)