Latent inhibition and facilitation of conditioned taste aversion in preweanling rats.

Early in ontogeny, taste preexposure has been found to induce latent inhibition as well as produce a facilitation of conditioned taste aversion (CTA). In this study, the effect of taste preexposure on CTA was investigated in 13-14 day old rats as a function of taste preexposure (0, 1, or 3 trials) and unconditioned stimulus intensity (LiCl: 0, 0.15, or 0.

Exposure to ethanol on prenatal days 19-20 increases ethanol intake and palatability in the infant rat: involvement of kappa and mu opioid receptors.

Prenatal exposure to ethanol on gestation Days 19-20, but not 17-18, increases ethanol acceptance in infant rats. This effect seems to be a conditioned response acquired prenatally, mediated by the opioid system, which could be stimulated by ethanol's pharmacological properties (mu-opioid receptors) or by a component of the amniotic fluid from gestation-day 20 (kappa-inducing factor). The latter option was evaluated administering non-ethanol chemosensory stimuli on gestation Days 19-20 and testing postnatal intake and palatability.

Prenatal binge ethanol exposure on gestation days 19-20, but not on days 17-18, increases postnatal ethanol acceptance in rats.

Previous research shows that prenatal binge ethanol exposure during gestation days (GD) 17 to 20 of the rat, increases postnatal ethanol intake and enhances ethanol's palatability, both effects being mediated by the opioid system. The amniotic fluid of the last period of gestation (GD 20) of the rat has been found to activate the opioid system and to induce conditioned preference in fetal and neonatal rats. We aimed to investigate whether enhanced acceptance for ethanol is observed when rat fetuses are exposed to it either on GD 17-18 or on GD 19-20.

The effect of taste familiarity on intake and taste reactivity in infant rats.

With infant rats, unlike with adults, increased intake of a taste after mere exposure to this stimulus is not consistently found; this has sometimes been interpreted as a failure by the immature subject to recognize tastes as familiar. We studied the effect of preexposure to a tastant, measuring taste reactivity and intake in 14-day-old rats. Familiarity increased hedonic response to sucrose, but also increased aversive response to quinine and ethanol.