Brief Exposures to the Taste of Ethanol (EtOH) and Quinine Promote Subsequent Acceptance of EtOH in a Paradigm that Minimizes Postingestive Consequences

Abstract

Increased EtOH acceptance following exposure is, at least in part, facilitated by a decrease in its aversive sensory properties. Both long- and short-term access increase the palatability of the taste of EtOH in brief-access licking tests. Moreover, the sensitivity to the bitterness of quinine was predictive of acceptance of EtOH indicating some commonality in the sensory mechanisms that mediate the initial acceptance of the 2 stimuli. Accordingly, immediate prior exposure to quinine results in increased acceptance of EtOH, suggesting that successive positive contrast between oral stimuli may contribute to increased alcohol consumption.

Nicotine pre-treatment reduces sensitivity to the interoceptive stimulus effects of commonly abused drugs as assessed with taste conditioning paradigms

“…Moreover, we observed attenuation of appetitive CTR following repeated EtOH self-administration, indicating that nicotine pre-exposure did not solely impact aversive stimulus properties. Brief exposures to the taste of EtOH result in rapid, substantial increases in the palatability of EtOH (Loney and Meyer, 2018). Here, we show that nicotine pre-treatment significantly limits this increase in acceptance (Fig 6).…”

“…On day 2, rats were again injected with their assigned drug, and then given 30-min access to a novel 0.1% saccharin solution (CS+) followed immediately by administration of the US (ethanol, morphine, cocaine, saline or LiCl). Nicotine was administered on each day of testing in an attempt to ensure that nicotine itself did not serve as a US and that it did not serve as an occasion setter predicting US administration Bevins and Palmatier (2004). This two-day pattern was repeated for a total of four CS+ and US pairings.…”

“…Repeated, brief self-administrations of EtOH result in appetitive CTR as evidenced by a substantial increase in licking generated by higher concentrations of EtOH following prior experience (Loney and Meyer, 2018). Here, we tested if the effects of nicotine in the pre-exposure paradigm were specific to avoidance CTR by examining the effect of nicotine pre-treatment on appetitive CTR induced by EtOH.…”

“…Rats were trained to consume water from the Davis rig as described previously (Loney and Meyer, 2018). Briefly, rats were adapted to the fluid presentation schedule in the Davis rig for 30-min sessions across 5-consecutive days.…”

“…This is in contrast to the effects of primarily emetic stimuli, such as lithium chloride (LiCl), which result in both conditioned place and taste avoidance (CPA and CTA, respectively; Parker, 2003; Tenk et al, 2005, 2006). Conversely, drug self-administration under some conditions can increase the acceptance of paired orosensory stimuli (Loney and Meyer, 2018), as defined by a relative reduction in rejection, suggestive of an increase in palatability. These positive and negative changes in hedonic stimulus value, (i.e.,, conditioned taste revaluation; CTR) are often used to assess sensitivity to drug reinforcement (Imperio and Grigson, 2015; Jenney et al, 2016), and can be used to infer changes in the interoceptive stimulus properties of a given drug.…”