Brain ethanol levels in rats after voluntary ethanol consumption using a sweetened gelatin vehicle

Abstract

A novel procedure for initiation of voluntary ethanol consumption in the rat was evaluated in terms of ease of initiation, consistency, and resulting brain ethanol levels. The "jello shot" consists of 10% ethanol in gelatin along with a caloric source (Polycose). Initiation of "jello shot" consumption in Sprague-Dawley rats required no food or water restriction and resulted in initial daily (8.4±0.6 g/kg body weight) and eventual hourly (1.1±0.1 g/kg body weight) intake of ethanol comparable to other procedures using either alcohol-preferring or non-genetically selected rats. Rat intake of ethanol via "jello shots" recovered quickly from environmental alterations and surgical implantation of a guide cannula. During 1-hr free access sessions, consumption of the "jello shot" occurred during the initial 10 minutes and resulted in a dose-related increase in ethanol levels in nucleus accumbens measured using microdialysis. These brain ethanol levels were comparable to those achieved using other selfadministration methods. However, when 0.5 g/kg ethanol was gavaged either in "jello shot" or saline, there was about a 20% decrease in brain ethanol concentrations after gavage of the "jello shot" compared to saline. Even so, lack of a need for initial food or water deprivation and the rapidity with which stable self-administration can be achieved both suggest utility of the "jello shot" as a completely voluntary ethanol procedure. Keywordsethanol self-administration; water deprivation; nucleus accumbens; gelatin; Polycose Alcohol ranks second only to tobacco in terms of the magnitude of adverse public health consequences of its abuse. It is important to develop animal models that emulate conditions of human abuse in order to study neural mechanisms implicated in the etiology of alcoholism. Animal models of alcoholism usually induce animals to drink sufficient quantities of ethanol by initial temporary food or water restriction to encourage rats to partake of unfamiliar tastes. For example, Czachowski et al. (1999) initiates ethanol consumption by providing the 10% ethanol solution as the only available fluid for three days before operant training. Additionally, the fluid received as a result of barpressing is the only fluid available during the first 5-7 days of operant training. Even when sucrose or saccharin is added to the ethanol solution to provide additional reinforcement, rats still need to be initially water deprived in order to encourage them to consume the novel sweet taste (reviewed in Samson & Czachowski 2004). Another 1 Mail proofs to:Joanna Peris, Ph.D. Department of Pharmacodynamics, Box 100487, University of Florida, Gainesville FL 32610, Phone: 352-392-9768, Fax: 352-392-9187, Email: peris@cop.ufl.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is pub...

Risk preference following adolescent alcohol use is associated with corrupted encoding of costs but not rewards by mesolimbic dopamine

“…Adolescent rats [postnatal day (PND) [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] were provided with continuous access to gelatin shots (10% EtOH or control gelatin) for 20 d (Fig. 1A).…”

“…Jars were sealed and refrigerated overnight. This procedure was designed to minimize evaporation of ethanol and has been validated to yield accurate ethanol content (29) and to lead to alterations in brain chemistry (30,31). Alcohol presentation involved allowing jars of gelatin to warm to room temperature and recording their weight.…”

Consequences of Adolescent Ethanol Consumption on Risk Preference and Orbitofrontal Cortex Encoding of Reward

“…Still, it is alarming that even moderate levels of intake, when consumed chronically during adolescence, exerted significant effects on both behavior and neurophysiology. While the gelatin vehicle used here is becoming increasingly common (Clark et al, 2012;Nasrallah et al, 2009Nasrallah et al, , 2011Peris et al, 2006), it is still a relatively new consumption model. In our hands, animals consuming control gelatin ate considerably more gelatin than both the alcohol groups.…”

“…To account for the calorie discrepancy between Ethanol and Control gelatin, the percentage of polycose was increased in the Control diet, such that the diets were calorie-matched by volume. Gelatin was provided to all animals using a modified 'drinking-inthe-dark-multiple-scheduled-access' paradigm (Bell et al, 2006(Bell et al, , 2011Peris et al, 2006), which permitted access at the onset of the dark cycle for 12 h on PD 29 and PD 30, 6 h on PD 31, 3 h on PD 32, and 1 h daily from PD 33 to PD 49. On the pre-exposure day (PD 29), all animals were given 12 h overnight access to control gelatin to reduce neophobia during the first EtOH gelatin access period.…”

Long-term risk preference and suboptimal decision making following adolescent alcohol use

“…Intake of these alcohol ''Jello Shots'' resulted in significant elevations of blood alcohol concentrations (6) in the range of 5 to 45 mg % with a linear relationship to amount consumed (r ϭ 0.94). Furthermore, alterations in brain chemistry in association with this administration protocol have also been documented (7)(8). Since this delivery method does not require training to promote intake, it is particularly appropriate for developmental studies, such as those focused on adolescence, since, in rodents, this period is relatively brief.…”