A comparison between taste avoidance and conditioned disgust reactions induced by ethanol and lithium chloride in preweanling rats

Center for Developmental Psychobiology, Binghamton University, Binghamton, NY 13902-6000, USA.
Developmental Psychobiology (Impact Factor: 3.31). 09/2010; 52(6):545-57. DOI: 10.1002/dev.20460
Source: PubMed


Adult rats display taste avoidance and disgust reactions when stimulated with gustatory stimuli previously paired with aversive agents such as lithium chloride (LiCl). By the second postnatal week of life, preweanling rats also display specific behaviors in response to a tastant conditioned stimulus (CS) that predicts LiCl-induced malaise. The present study compared conditioned disgust reactions induced by LiCl or ethanol (EtOH) in preweanling rats. In Experiment 1 we determined doses of ethanol and LiCl that exert similar levels of conditioned taste avoidance. After having equated drug dosage in terms of conditioned taste avoidance, 13-day-old rats were given a single pairing of a novel taste (saccharin) and either LiCl or ethanol (2.5 g/kg; Experiment 2). Saccharin intake and emission of disgust reactions were assessed 24 and 48 hr after training. Pups given paired presentations of saccharin and the aversive agents (ethanol or LiCl) consumed less saccharin during the first testing day than controls. These pups also showed more aversive behavioral reactions to the gustatory CS than controls. Specifically, increased amounts of grooming, general activity, head shaking, and wall climbing as well as reduced mouthing were observed in response to the CS. Conditioned aversive reactions but not taste avoidance were still evident on the second testing day. In conclusion, a taste CS paired with postabsorptive effects of EtOH and LiCl elicited a similar pattern of conditioned rejection reactions in preweanling rats. These results suggest that similar mechanisms may be underlying CTAs induced by LiCl and a relatively high EtOH dose.

Download full-text


Available from: Norman E. Spear, Oct 02, 2015
91 Reads
  • Source
    • "Nevertheless, before and during this ontogenetic window, aversive conditioning has been described when lithium chloride acts as an US (Gruest et al. 2004; Miller et al. 1990; Molina et al. 1986). This substance induces internal malaise and disgust reactions similar to those observed following EtOH intoxication and shares common biological substrates with EtOH's aversive effects (Arias et al. 2010). A matter of special concern when addressing EtOHderived reinforcing effects is the drug's potential to also alter "
    [Show abstract] [Hide abstract]
    ABSTRACT: RATIONALE: Animal studies indicate that central acetaldehyde, dependent on catalase metabolism of ethanol (EtOH), modulates ethanol reinforcement. Brain catalase activity and acetaldehyde (ACD) production are significantly higher in rat pups compare d with adults. Interestingly, infant rats show high EtOH affinity for alcohol consumption and are particularly sensitive to the drug's reinforcing effects. OBJECTIVES: We tested whether central ACD is necessary and sufficient to induce appetitive conditioning in newborn rats through the artificial nipple technique. METHODS: Vehicle, EtOH (100 mg%), and acetaldehyde (0.35 μmol) were administered into the cisterna magna (1 μl). Half of the animals also received a central administration of 75 μg (experiment 1) or 40 μg of D-penicillamine (experiment 2). Afterwards, pups were exposed to an olfactory cue (conditioned stimulus). One hour later, neonates were tested with an artificial nipple in the presence of the conditioned cue. Nipple attachment duration, mean grasp duration, and number of nipple disengagements served as dependent variables. RESULTS: Positive responses to the scented nipple occurred in neonates conditioned with EtOH or ACD (experiments 1 and 2). In experiment 1, there were indications that D-penicillamine weakened the reinforcing effects of EtOH and ACD. In experiment 2, D-penicillamine (40 μg) significantly inhibited appetitive conditioned responses dependent upon EtOH or ACD. CONCLUSIONS: Appetitive conditioning was observed when employing either central EtOH or ACD as unconditioned stimuli. Central abduction of ACD inhibited conditioned appetitive responsiveness to the surrogate nipple. Central ACD is involved in the determination or modulation of EtOH's motivational properties during early stages in development.
    Psychopharmacology 12/2012; 226(3). DOI:10.1007/s00213-012-2920-9 · 3.88 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: When amphetamine is associated with a tastant conditioned stimulus, rats learn to avoid the taste even when employing doses that promote conditioned place preference. One hypothesis raised to account for this effect proposes that taste avoidance induced by amphetamine may be motivated by fear. A sensitive period has been identified in the rat (until postnatal day 10) in which infants learn conditioned appetitive effects to stimuli to which aversions are conditioned after this period. Exogenous administration of corticosterone within this period reverses this effect, generating aversive conditioning. In the present study, we tested conditioning of aversions to amphetamine or LiCl, within and after the sensitive period (Experiments 1 and 2). A third experiment evaluated unconditioned rejection of an aversive quinine solution within the sensitive period. Finally, we tested whether corticosterone administration before conditioning modulates amphetamine-induced taste avoidance. After the sensitive period, infant rats rejected the solution paired with amphetamine or LiCl after 2 conditioning trials, but within the sensitive period, aversions were conditioned only by LiCl and after 4 conditioning trials. Amphetamine-induced taste avoidance was not observed even when corticosterone was administered before conditioning. Additionally, during the sensitive period, a low LiCl dose promoted conditioned taste preference. According to Experiment 3, parameters employed in this study were suitable to yield rejection of aversive solutions within the sensitive period. These results suggest that during the sensitive period, there is a notable resistance to the acquisition of taste avoidance induced by amphetamine. The present experimental framework may represent a useful tool for studying mechanisms underlying taste avoidance and aversion effects.
    Chemical Senses 03/2011; 36(6):565-77. DOI:10.1093/chemse/bjr026 · 3.16 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study evaluated consummatory responses in infant rats exposed to different magnitude of reward, and after the devaluation (i.e., consummatory successive negative contrast) or omission (i.e., extinction) of reward. In Experiment 1, 8-10 post-natal days (PND) pups were intraorally infused with 12%, 10%, 5% or 2% sucrose (preshifit phase, 2 daily trials). Subsequently, all groups received 2% sucrose (postshift phase). In Experiment 2, 10-14 day-old pups received 12% or 2% sucrose in 4 daily trials in the preshift phase, followed by 2% in a postshift trial. Both experiments indicated that during preshifit, animals exposed to 12% sucrose exhibited higher sucrose consumption than those receiving lower concentration solutions. This phenomenon, indicative of a magnitude of reinforcement effect was not accompanied by evidence of successive negative contrast. In Experiment 3 we evaluated the magnitude of reinforcement extinction effect in 7-12 PND rats. Animals received 12% sucrose or water in preshifit phase and both groups received a neutral solution (i.e., water) in the second phase. A magnitude of reinforcement acquisition effect was again observed, yet there were no differences between groups in extinction phase. In Experiment 4 we used an anticipatory contrast procedure in 10-16 PND pups. A magnitude of reinforcement, but not an anticipatory contrast effect was observed. Overall the results indicate that: (a) rats from - at least- 8 PND discriminate between different concentrations of sucrose, and (b) until the second week of life the response to rewards is mainly regulated by their absolute value and not by their relative value. Results are discussed terms of the ontogeny of paradoxical effects of reward and its relationship to Amsel's theory.
    Suma Psicologica 01/2012; 19(1):19-31.
Show more