An improved technique for monitoring the drinking behavior of mice

LIQ HD (Lick Instance Quantifier Home Cage Device): An Open-Source Tool for Recording Undisturbed Two-Bottle Drinking Behavior in a Home Cage Environment

Investigation of rodent drinking behavior has provided insight into drivers of thirst, circadian rhythms, anhedonia, and drug and ethanol consumption. Traditional methods of recording fluid intake involve weighing bottles, which is cumbersome and lacks temporal resolution. Several open-source devices have been designed to improve drink monitoring, particularly for two-bottle choice tasks. However, beam-break sensors lack the ability to detect individual licks for bout microstructure analysis. Thus, we designed LIQ HD (Lick Instance Quantifier Home cage Device) with the goal of using capacitive sensors to increase accuracy and analyze lick microstructure, building a device compatible with ventilated home cages, increasing scale with prolonged undisturbed recordings, and creating a design that is easy to build and use with an intuitive touchscreen graphical user interface. The system tracks two-bottle choice licking behavior in up to 18 rodent cages, or 36 single bottles, on a minute-to-minute timescale controlled by a single Arduino microcontroller. The data are logged to a single SD card, allowing for efficient downstream analysis. LIQ HD accuracy was validated with sucrose, quinine, and ethanol two-bottle choice tasks. The system measures preference over time and changes in bout microstructure, with undisturbed recordings tested up to 7 d. All designs and software are open-source to allow other researchers to build on the system and adapt LIQ HD to their animal home cages.

Home-Cage Sipper Devices Reveal Age and Sex Differences in Ethanol Consumption Patterns

Free-choice paradigms such as two-bottle choice (2BC) are commonly used to characterize ethanol consumption and preference of rodent models used to study alcohol use disorder (AUD). However, these assays are limited by low temporal resolution that misses finer patterns of drinking behavior, including circadian drinking patterns that are known to vary with age and sex and are affected in AUD pathogenesis. Modern, cost-effective tools are becoming widely available that could elucidate these patterns, including open-source, Arduino-based home-cage sipper devices. We hypothesized that adaptation of these home-cage sipper devices would uncover distinct age- and sex-related differences in temporal drinking patterns. To test this hypothesis, we used the sipper devices in a continuous 2BC paradigm using water and ethanol (10%; v/v) for 14 days to measure drinking patterns of male and female adolescent (3-week), young adult (6-week), and mature adult (18-week) C57BL/6J mice. Daily grams of fluid consumption were manually recorded at the beginning of the dark cycle, while home-cage sipper devices continuously recorded the number of sips. Consistent with prior studies, females consumed more ethanol than males, and adolescent mice consumed the most out of any age group. Correlation analyses of manually recorded fluid consumption versus home-cage sipper activity revealed a statistically significant prediction of fluid consumption across all experimental groups. Sipper activity was able to capture subtle circadian differences between experimental groups, as well as distinct individual variation in drinking behavior among animals. Blood ethanol concentrations were significantly correlated with sipper data, suggesting that home-cage sipper devices can accurately determine individual timing of ethanol consumption. Overall, our studies show that augmenting the 2BC drinking paradigm with automated home-cage sipper devices can accurately measure ethanol consumption across sexes and age groups, revealing individual differences and temporal patterns of ethanol drinking behavior. Future studies utilizing these home-cage sipper devices will further dissect circadian patterns for age and sex relevant to the pathogenesis of AUD, as well as underlying molecular mechanisms for patterns in ethanol consumption.

Highlights

Female mice consume more ethanol than males in a continuous access paradigmAdolescent male and female mice consume more ethanol than young or mature adult miceAutomated home-cage sipper devices accurately measure ethanol consumptionDevices reveal sex- and age-dependent differences in circadian drinking patternsDevices reveal distinct individual variation in circadian drinking patterns.

Leveraging calcium imaging to illuminate circuit dysfunction in addiction

Alcohol and drug use can dysregulate neural circuit function to produce a wide range of neuropsychiatric disorders, including addiction. To understand the neural circuit computations that mediate behavior, and how substances of abuse may transform them, we must first be able to observe the activity of circuits. While many techniques have been utilized to measure activity in specific brain regions, these regions are made up of heterogeneous sub-populations, and assessing activity from neuronal populations of interest has been an ongoing challenge. To fully understand how neural circuits mediate addiction-related behavior, we must be able to reveal the cellular granularity within brain regions and circuits by overlaying functional information with the genetic and anatomical identity of the cells involved. The development of genetically encoded calcium indicators, which can be targeted to populations of interest, allows for in vivo visualization of calcium dynamics, a proxy for neuronal activity, thus providing an avenue for real-time assessment of activity in genetically and anatomically defined populations during behavior. Here, we highlight recent advances in calcium imaging technology, compare the current technology with other state-of-the-art approaches for in vivo monitoring of neural activity, and discuss the strengths, limitations, and practical concerns for observing neural circuit activity in preclinical addiction models.

An open-source lickometer and microstructure analysis program

Described herein is a design for a user-constructed electronic lickometer, intended to allow users to conduct relatively simple behavioral experiments with rodents while avoiding several common stumbling blocks. Primarily, this system does not require the purchase of specialized scientific equipment or software. Additionally, it is possible for users to construct and operate this lickometer without the prerequisite of advanced knowledge of electronics or programming. Overall, the goal of this apparatus is to provide a simple and affordable alternative for users seeking to study ingestion behaviors in rodents, while still allowing the user to obtain high-resolution data and conduct sophisticated microstructural analysis of the behavior in question. All of this is achieved using low-cost and commonly available materials for the construction of the apparatus itself, and open-source software to collect and analyze data. The only substantial prerequisites for this design are a PC with a 3.5 mm microphone input and a comfortable understanding of power tools. Finally, a validation of the operation of the describe apparatus is included.

Chrna5 genotype determines the long-lasting effects of developmental in vivo nicotine exposure on prefrontal attention circuitry

Maternal smoking during pregnancy repeatedly exposes the developing fetus to nicotine and is linked with attention deficits in offspring. Corticothalamic neurons within layer VI of the medial prefrontal cortex are potential targets in the disruption of attention circuitry by nicotine, a process termed teratogenesis. These prefrontal layer VI neurons would be likely targets because they are developmentally excited and morphologically sculpted by a population of nicotinic acetylcholine receptors (nAChRs) that are sensitive to activation and/or desensitization by nicotine. The maturational effects of these α4β2* nAChRs and their susceptibility to desensitization are both profoundly altered by the incorporation of an α5 subunit, encoded by the chrna5 gene. Here, we investigate nicotine teratogenesis in layer VI neurons of wildtype and α5(-/-) mice. In vivo chronic nicotine exposure during development significantly modified apical dendrite morphology and nAChR currents, compared with vehicle control. The direction of the changes was dependent on chrna5 genotype. Surprisingly, neurons from wildtype mice treated with in vivo nicotine resembled those from α5(-/-) mice treated with vehicle, maintaining into adulthood a morphological phenotype characteristic of immature mice together with reduced nAChR currents. In α5(-/-) mice, however, developmental in vivo nicotine tended to normalize both adult morphology and nAChR currents. These findings suggest that chrna5 genotype can determine the effect of developmental in vivo nicotine on the prefrontal cortex. In wildtype mice, the lasting alterations to the morphology and nAChR activation of prefrontal layer VI neurons are teratogenic changes consistent with the attention deficits observed following developmental nicotine exposure.

A Balance Device for the Analysis of Behavioural Patterns of the Mouse

A device for analysing mouse behaviour which is based on recording the movements of the animal in a balance test cage has been developed. The amplitude patterns provoked by the movements of the animal correlate with behavioural patterns. The system not only allows differentiation between five behavioural categories: resting, grooming, eating, locomotion and climbing - but also indicates the location of the animal in its cage. Upon validation, the system has proven to be a reliable and time-saving device for the non-invasive recording of behavioural patterns in the mouse.

Effects of continuous versus limited access to ethanol on ethanol self-administration

Eight male, experimentally naive Long-Evans rats were housed in operant chambers 23 h per day following initiation to self-administer ethanol. While housed in the chambers, the animals had continuous access to food pellets according to a fixed ratio 1 schedule of reinforcement, 10% ethanol (v/v) according to a fixed ratio 4 schedule of reinforcement and water in a drinking tube with licks recorded via a drinkometer. Over a series of experimental phases, daily availability of the ethanol solution was limited to 16, 6, 4, 2, or 1 30-min period per day. The 1 30-min period access was examined during the 12th hour or the second hour of the daily sessions. Over the course of the experiment, total responses on the lever that operated the dipper, g/kg per day and number of ethanol drinking bouts per day decreased significantly as the number of daily access periods decreased. On the other hand, the number of dippers presented per ethanol bout, g/kg per ethanol bout and ethanol bout duration increased, with significant increases in dippers per bout occurring when one 30-min access period per day was provided. These data indicate that the size of a single ethanol drinking bout can be increased somewhat by limiting the opportunity to obtain ethanol reinforcement and agrees with earlier research that has shown similar effects.

Intestinal expression of human apolipoprotein A-IV in transgenic mice fails to influence dietary lipid absorption or feeding behavior

Two transgenic mouse lines, expressing low or high amounts of human apo A-IV were created. In low and high expressor HuAIVTg mice on a chow diet, serum human apo A-IV levels were 6 and 25 times the normal human level and on a high fat diet, they were 12 and 77 times higher. Human apo A-IV was equally distributed between lipoprotein (mainly HDL) and lipid-free fractions. Intestinal absorption of radiolabeled cholesterol and triglycerides was unaffected in HuAIVTg mice. Vitamin A, carried exclusively in chylomicrons and their remnants, was catabolized normally. When an intragastric vitamin E bolus is given to the HuAIVTg mice, the initial absorption and appearance in triglyceride-rich lipoproteins was similar to that observed in normal mice. However, elevated amounts of vitamin E were subsequently observed in the VLDL of the HuAIVTg mice. Furthermore, in the fed state, serum VLDL triglycerides were markedly elevated in HuAIVTg mice. This effect was greater in high expressor mice. Serum total cholesterol was not elevated, but the distribution was altered in the HuAIVTg mice; VLDL-C was increased at the expense of VLDL-C. Kinetic studies suggested a delayed clearance of VLDL in HuAIVTg mice. Apo A-IV has been suggested to be a satiety factor, but no effect on feeding behavior or weight gain was observed in these HuAIVTg mice. In summary, our studies with HuAIVTg mice show that additional apo A-IV does not effect intestinal absorption of fat and fat-soluble vitamins, and at least chronic elevation of plasma apo A-IV does not effect feeding behavior in this model system.

Neuropeptide Y attenuates satiety: evidence from a detailed analysis of patterns ingestion

Centrally injected neuropeptide Y (NPY) is a potent stimulant of ingestive behavior capable of augmenting both food and fluid intake in fully satiated animals. To gain further insight into NPY's mechanism of action, we recorded patterns of licking behavior in rats drinking sweetened condensed milk solutions immediately after lateral ventricular injection of NPY (10 micrograms) or vehicle. In a separate study, we examined licking patterns after 23 h food deprivation (FD) that produced approximately the same total intake as NPY. Consistent with previous reports, we found NPY stimulated intake by increasing total ingestion time and total volume consumed during a 1-h test. Although NPY increased the number of bouts of licking and shortened pauses between bouts, it also decreased mean bout size, bout duration and within-bout lick rate (local rate). It had no significant effect on start latency or lick efficiency (licks/ml). Further analyses revealed that NPY attenuated satiety (reduced slope of lick-rate functions with session time) but had no significant effect on the beginning lick rate, a measure related to orosensory excitation. In contrast to NPY, FD increased both the beginning lick rate and individual bout size without changing either the mean number of bouts or the pause between bouts. In general, NPY stimulated an intermittent pattern of licking and delayed satiation whereas FD increased the initial rate of licking and the size of individual bouts without changing the basic licking pattern. The increase in initial lick rate suggests that FD, unlike NPY, enhances orosensory stimulation. These data compliment previous results showing that NPY increases the motivation to eat.(ABSTRACT TRUNCATED AT 250 WORDS)

Disruption of body temperature and behavior rhythms during reproduction in dwarf hamsters (Phodopus)

The internal gestation and subsequent lactation of mammalian reproduction represent a considerable physiological challenge. The extent of disruption in the daily rhythm of four parameters, core body temperature, nest attendance, activity, and wheel running, was monitored in Djungarian hamster (Phodopus campbelli) and Siberian hamster (P. sungorus) females implanted intraperitoneally with biotelemetric thermistors. The amplitude of each rhythm decreased during late gestation, culminating in a substantial disruption at parturition, and did not begin a recovery until the latter third of lactation. In each species, the change in the core body temperature rhythm was primarily the result of an elevation in light phase body temperature to approximate the normally occurring dark phase temperature, although the disruption was more extensive in P. sungorus than in P. campbelli. As this maternal hyperthermia is associated with the provision of essential heat to the altricial liter, these species differences in the vulnerability to hyperthermia may constrain the reproductive success of these extreme cold adapted small mammals.

EtOH self-administration in anticipation of noise stress in C57BL/6J mice

C57BL/6J mice were studied for self-administration of ethanol (EtOH) during a signal period that preceded delivery of an environmental stressor (noise) in the home cage. Animals were given 5 weeks of conditioning in which a 5-min period of 75-dB pulsed noise (SIGNAL) preceded a 20-min period of more intense, 90-dB pulsed noise (NOISE) five times daily. EtOH (10% w/v) was then provided in a choice procedure, and drink tube contacts were monitored by computer. Mice that had received the 5 weeks of SIGNAL and NOISE pairings showed an increase in EtOH-seeking behavior, as reflected in EtOH tube contacts during the SIGNAL period. The increase was significant as compared to contacts during baseline or QUIET periods and also as compared to contacts during the same period for control (Ctrl) mice that had received only the 75-dB SIGNAL during conditioning. A subsequent test for passive avoidance confirmed that the 75-dB SIGNAL was aversive for mice that had received noise conditioning but not for Ctrl mice. In sum, the results were in accord with a priori predictions that mice would not show increased EtOH tube contacts during occurrence of intense noise itself but would show increased contacts during the signal that preceded noise. These results were interpreted as preliminary evidence that C57BL/6J mice show self-administration of EtOH in anticipation of an environmental stressor.

Effects of bombesin on temporal patterns of ingestion in the rat

Bombesin, an analog to gastrin releasing peptide, has previously been shown to inhibit food intake in the rat. In order to further characterize the effects of bombesin on ingestive behavior, the present study examined licking patterns of rats drinking sweetened condensed milk following bombesin (4 micrograms/kg, IP) or vehicle injection under two levels of food deprivation (0 and 24 h). Both bombesin treatment and satiety (reducing food deprivation from 24 to 0 h) significantly decreased total milk consumption during a 1-h test. Analysis of licking patterns suggested that bombesin and satiety operate by similar but not identical mechanisms. Deprivation reduction tended to decrease ingestion by reducing the rate of drinking and size of the first meal. Bombesin, by contrast, reduced the total duration of drinking and the number of meals taken, but had no effect on lick rate. Cumulative intake records suggested that bombesin reduces the volume threshold for termination of drinking such that intake continues at a normal rate below this threshold but ceases above it. This bombesin-imposed threshold for cessation of drinking was between about 5 and 7 ml for individual animals under both food-deprived and nondeprived testing conditions.

Adrenalectomy, corticosteroid replacement and their importance for drug-induced memory-enhancement in mice

Adrenalectomy blocks the memory-improving effect of piracetam-like compounds in mice. If this blockade is due to the removal of endogenous corticosteroids, replacement therapy with exogenous corticosteroids should reinstate the effects on memory. The present experiments were designed to determine the appropriate replacement dose (concentration in the drinking fluid) for corticosterone and aldosterone, the main corticosteroids in mice. Based on the effects of corticosterone on thymus weight, replacement with 3 micrograms/ml corticosterone given in the drinking fluid (0.9% NaCl) for one week was found to be appropriate. The appropriate replacement dose for aldosterone was found by giving aldosterone to adrenalectomized (ADX) mice in the drinking fluid in combination with 3 micrograms/ml corticosterone. The combination of 3 micrograms/ml corticosterone + 30 ng/ml aldosterone resulted in a plasma ratio of corticosterone/aldosterone which most closely approximated the ratio seen in sham-ADX control animals. The physiologic adequacy of the corticosteroid replacement doses resulting from this study were clearly demonstrated in subsequent behavioral experiments where blockade of the memory-enhancing effects of piracetam by adrenalectomy were overcome by replacement with either 3 micrograms/ml corticosterone or 30 ng/ml aldosterone given in the drinking fluid.

Lick sensors as tools in behavioral and neuroscience research

Lick sensors can be valuable tools in behavioral and neuroscience research on licking and drinking behavior. The focus of this discussion is the recording of licking in the rat. However, comments on the application of these sensors to the measuring of fluid intake are included as well. Lick sensors should be used with adequate precautions. Some constraint on the access of the animal to the drinking tube is necessary for the adequate recording of each single lick. Published drawbacks to the use of electrically operated lick sensors are discussed, and reduced to realistic proportions. With these latter sensors one can obtain behavioral and electrophysiological data that are directly related to the time of making and breaking contact of the tongue with the fluid that is drunk.

Early experience and the consumption of alcohol by adult C57BL/6J mice

Two types of early experience were examined for their effect on voluntary alcohol consumption by adult C57BL/6J mice: the experiences associated with belonging to a particular litter, and the experience of early postweaning choice between water and a 10% alcohol solution. Males from identified litters were individually caged from arrival at three weeks of age and given a choice between 10% alcohol and water when eight weeks old. Another group without notation of litter was given alcohol-water choice upon arrival at three weeks of age. Alcohol intake was examined by three measures: daily licks of 10% alcohol, alcohol selection (percent alcohol drinking), and volume of alcohol drunk daily. Belonging to a particular litter did affect body weight and growth, but had no effect on adult consumption of alcohol. Postweaning exposure to alcohol choice, however, produced a small but significant and prolonged increase in alcohol consumption by adults. Furthermore, a developmental trend was found in mice offered alcohol choice at an early age: alcohol preference developed as postweaning growth slowed.

A microcomputer controlled data acquisition system for research on feeding and drinking behavior in rats

This paper describes an inexpensive, reliable computer controlled data collection system designed for the continuous monitoring of feeding and drinking behavior in rats. This system will be useful in areas of behavioral pharmacology research requiring a detailed analysis of food and fluid intake. The configuration described herein was developed for research on the "microstructure" of alcohol drinking behavior. Variables examined include: alcohol bout size, frequency and duration, interbout intervals as well as the temporal pattern of intake and its relationship to food and water consumption. Detailed analysis of behavior using this technique will enhance our ability to interpret the nature of changes in alcohol oriented behavior produced by pharmacological manipulations, aid in the development of specific hypotheses related to the regulation of alcohol drinking behavior and provide a means of testing these hypotheses.

Manipulation of alcohol preference in C57BL/6J mice by episodes of food poisoning

Individual differences in the amount of alcohol consumed in a choice situation are found in highly inbred C57BL/6J mice. The extent to which environmental stress can modify alcohol preference was studied by coupling acute episodes of poisoning with restricted fluid availability, and recovery with free choice of drinking fluids. Addition of actinomycin D, a mycotoxin, to ordinary chow during 2-day periods produced acute episodes of nonlethal food poisoning from which the mice recovered rapidly. Consumption of a 10% alcohol solution and of water was recorded for several weeks before poisoning and for several weeks after the last episode. By varying drinking fluids available to the mice during the episodes of poisoning, long-lasting changes in alcohol preference were produced. When 10% alcohol was the sole drinking fluid available during poisoning, preference for the alcohol solution was abolished. When water was the sole fluid during poisoning, alcohol preference was increased above the already high levels established in the baseline and above a control group that was restricted to water during the treatment periods but was not poisoned. This increased alcohol preference was due to a nearly complete suppression of water intake in the posttreatment period; there was no significant increase in amount of alcohol consumed. The greatest individual differences in subsequent alcohol preference were found in the group of mice which continued to have free choice of alcohol and water during episodes of poisoning. The variety of responses to the same treatment show how environmental influences outside the experimenter's control may account for the variability found in voluntary alcohol consumption among genetically homogeneous mice.

Toward an analogue of alcoholism in mice: analysis of nongenetic variance in consumption of alcohol

Drinking behavior of the isogenic mouse strain C57BL/6J was analyzed into nongenetic components: stochastic fluctuations, responses to fluctuations in the current environment, and persistent differences between individual animals. The latter accounted for the major part of the variance. The variance was neither increased by differences in diet during the postweaning rapid growth period (prior to assay for drinking choice) nor diminished by uniformity of treatment during this period, suggesting that significant differentiation had occurred prior to weaning. The large variance between animals could be explained by assuming that the genetic role in consumption of alcohol by C57BL mice is permissive--a relative insensitivity to the aversive orosensory and pharmacological effects of 10% alcohol--rather than a specific drug-seeking predisposition.

Circadian feeding and drinking patterns of genetically obese mice fed solid chow diet

Feeding and drinking were recorded in male ob/ob mice and lean mice fed pelleted Purina Lab Chow No. 5001 with water to drink. The circadian patterns of eating and drinking of obese mice differed from those of lean mice, in both the proportional temporal distributions of feeding and of drinking behavior across the 24-hour day and in the absolute amounts consumed hourly. The pattern of increased food consumption by the obese mice was different than that underlying increased water consumption. When meal parameters were analyzed in terms of 'complete meals' of both feeding and drinking (the end of a meal defined as at least 12 consecutive minutes with no ingestion), obese and lean mice had the same number of meals and their periodicity was similar, but meal size was much greater in the obese mice. In the dark, both obese and lean mice showed strong postprandial correlations of meal size with time from the start of a meal to start of the next meal.

Why does a sucrose choice reduce the consumption of alcohol in C57BL/6J mice?

To determine why animals reject alcohol when offered palatable solutions of sucrose, male C57BL/6J mice were challenged first with 5% sucrose then with 10% sucrose, while given continuous free-access to alcohol and water. The 5% sucrose dramatically reduced the intake of alcohol and increased the intake of total fluid by an average of 7.3 ml/day. The suppression of alcohol intake could not be attributed to a volumetric ceiling since access to 10% sucrose produced a further large increase in total intake (8.8 ml/day). The results support the interpretation that animals consume alcohol for characteristics it shares with sucrose.

Circadian drinking rhythms and blood alcohol levels in two rat lines developed for their alcohol consumption

The circadian drinking behavior of the AA (Alko Alcohol) and ANA (Alko Non-Alcohol) rat lines developed for high and low voluntary alcohol consumption was studied by using a microcomputer lick-counting system. The blood alcohol concentrations of AA rats were measured during the drinking peaks. The results showed that AA rats voluntarily drink intoxicating amounts of alcohol. The highest blood alcohol levels were about 25 mmol/l. Differences in circadian drinking rhythms between AA and ANA lines were also found. AA rats had a trimodal drinking pattern for alcohol intake during the dark period but ANA rats drank alcohol rather evenly throughout the period.

An experimental model of self-intoxication in C57 mice

Male C57BL/6J mice offered unrestricted access to food, water and 10% ethanol, exhibited obvious intoxication when treated with the alcohol dehydrogenase inhibitor, 4-methylpyrazole (4MP) by chronic infusion. Plasma concentrations of ethanol ranged from 156 +/- 43 mg/dl at midday to 254 +/- 31 mg/dl at midnight producing a twenty-fold increase in the total exposure to blood alcohol. Illness sufficiently severe to require intervention occurred in five of the ten mice in the experimental group, while controls treated with 4MP and offered only water to drink displayed no adverse effects. The continuation of drinking despite life-threatening toxicity suggests these mice failed to make an association between the consumption of ethanol and its consequences.

Voluntary consumption of ethanol and its consequences in C57 mice treated with 4-methylpyrazole

Daily injections of the alcohol dehydrogenase inhibitor 4-methylpyrazole (4MP) were administered to C57BL/6J mice offered continuous free access to food, water and 10% v/v ethanol. There was a significant correlation (r = -0.82) between the rate of ethanol consumption during pretreatment and the effect of 4MP on subsequent intake. Mice drinking more than 2.5 g/kg per day decreased their intake, while subjects drinking less than this amount increased the quantity of ethanol self-administered. The elevated concentrations of plasma ethanol which resulted from voluntary consumption were sufficient to produce intoxication but did not induce physical dependence. Presenting mice with 10% ethanol as their only fluid or offering them a choice of water and saccharin-sweetened ethanol increased intake but failed to raise plasma ethanol to the concentrations observed in mice offered unflavored ethanol and water, and treated with 4MP. The evidence suggests that plasma ethanol does not limit voluntary drinking in untreated mice and that concentrations of 135 to 250 mg/dl are not avoided by C57 mice in a free-choice situation.

Toward an analogue of alcoholism in mice: criteria for recognition of pharmacologically motivated drinking

Two criteria of alcoholic drinking behavior--inelasticity of demand and dissociation of intake from normal eating and drinking--are illustrated by study of alcohol-preferring C57BL/6J mice. Although these mice drink enough to become intoxicated for brief periods each night, they do not meet the more rigorous criteria for pharmacologically motivated drinking. Their intake of alcohol was dramatically decreased when they were offered diets augmented with sugar or Crisco, and the temporal pattern of drinking was correlated with the intake of food. Thus, their motivation for drinking alcohol is related to nutrition and is not drug-seeking comparable to that of human alcoholics. Since the tests are simple and decisive, it might be useful to apply them to all putative models of alcoholism.

Computer based instruments for laboratory environments

The personal computer is viewed as an all-purpose laboratory instrument and work station. Popular architectures are examined with regard to advantages and limitations, and applications discussed in terms of "stand alone" environments, situations requiring passive interfaces, and those employing intelligent configurations. A new hardware/software architecture is presented which is highly modular, and which supports rapid instrumental reconfiguration, high throughput (information capacity), and ease of use.

Toward an analogue of alcoholism in mice: scale factors in the model

Mice of the C57BL strain, given continuous access to 10% alcohol and plain water, with unlimited food and no stress, frequently drink enough alcohol to produce intoxicating levels in the blood. Nevertheless, this behavior does not appear to replicate the essential features of human alcoholism since the drinking lacks serious toxic effects and the intoxication occurs only as transient episodes in association with homeostatic consumption of fluid and food. It is suggested that continuous monitoring of intake and estimation of the concentration of alcohol in blood, which are now technically feasible, will permit distinction between alcoholic-type drinking and a simple licking for the flavor of alcohol in beverage concentration.

Self-administration of ethanol by genetically heterogeneous mice (RU:NCS): relationship to sensitivity and tolerance

The interrelationships among sensitivity, tolerance and the self-administration of ethanol were studied in a non-inbred strain of mice. Blood ethanol concentration at the time of righting-loss following a hypnotic dose of ethanol (3.5 g/kg) was measured before and after 8 weeks exposure to a choice of water and ethanol water drinking solutions. The inter-test difference between blood ethanol concentration at loss of righting indicated that self-administration resulted in chronic tolerance. A correlational analysis indicated chronic tolerance, but not sensitivity, was positively correlated with ethanol intake and preference.

Elevated concentrations of ethanol in plasma do not suppress voluntary ethanol consumption in C57BL mice

The 24-hr patterns of ethanol intake and resulting concentrations of ethanol in plasma are described for male C57BL/6J mice given free access to water and a 10% v/v solution of ethanol. Animals treated with the alcohol dehydrogenase inhibitor 4-methylpyrazole developed peak plasma concentrations of 116 +/- 20 mg/100 ml, while controls given daily injections of saline exhibited peak plasma concentrations of 11 +/- 7 mg/100 ml. Ethanol consumption as measured by total daily intake and preference was not significantly different in the two groups of mice. The absence of an effect on ethanol consumption despite a tenfold difference in peak plasma levels suggests that concentrations of circulating ethanol within the range observed do not limit voluntary consumption of ethanol.