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Biomedical subjects

R A Meisch

Publications and source records attributed to R A Meisch.

At least 73 records · Page 4Linked to original sources
PubMed1982

The effects of food deprivation and satiation on oral pentobarbital self-administration in rhesus monkeys.

The effects of food deprivation and satiation on oral pentobarbital self-administration were studied in four rhesus monkeys. Pentobarbital (1.0 mg/ml) or water was available during alternate daily 3-hr session; between sessions, water was freely available. Lip contacts on a drinking spout activated a solenoid operated liquid delivery system. Liquid deliveries (0.56 ml) occurred after a fixed number of lip contact responses were emitted; that is, liquids were delivered according to fixed-ratio (FR) schedules. Under food deprivation conditions, pentobarbital-maintained behavior exceeded water-maintained behavior. Thus, pentobarbital functioned as a reinforcer. Abrupt unlimited access to food resulted in decreased pentobarbital intake. Pentobarbital-maintained behavior increased to previous levels when food intake was again restricted. In a second experiment, the effects of pentobarbital availability on water-maintained behavior were studied. Access to pentobarbital during alternate sessions produced elevated levels of water drinking during intervening sessions. Water drinking decreased to low levels when pentobarbital access was terminated and water was present for consecutive sessions. When pentobarbital was again available during alternate sessions, high levels of water drinking recurred. In the third experiment, water and pentobarbital (1.0 mg/ml) were concurrently available via separate drinking spouts. All three monkeys drank much more pentobarbital solution than water.

Administration, Oral↗
PubMed1981

Determinants of increased drug self-administration due to food deprivation.

Changes in oral etonitazene self-administration were compared in four groups of rats that were maintained at 100, 95, 85, or 75% of their pre-experimental free-feeding body weights. Etonitazene (5 micrograms/ml) or water was available for 16 h according to a fixed-ratio (FR) 1 schedule. Each liquid delivery (0.1 ml) was contingent upon a lever-press response. During food deprivation etonitazene intake gradually increased to over two-fold as body weights decreased over 25 sessions; etonitazene intake was inversely proportional to body weight. The 75% weight group showed stereotypy, self-mutilation and large variability in daily etonitazene intake. In another experiment a range of deprivation conditions was studied in a group of six rats with etonitazene (5 micrograms/ml) or water available on an FR 8 schedule during 1-h sessions. When the rats were gradually food satiated, etonitazene-maintained behavior declined but remained higher than water-maintained behavior; however, when they were abruptly food satiated, etonitazene-maintained behavior decreased to low levels.

Animals↗
PubMed1981

A precision drinking device for rats tested with water, etonitazene, and ethanol.

An inexpensive system for detecting tongue licking and for delivering liquids to rats is described. Liquids were dispensed under a heterogenous chain schedule of reinforcement in which depressions of a lever were required before tongue licking produced liquid delivery. Three rats drank water dispensed by the system at lowest, highest, and midmost valve settings. The volume of water delivered increased logarithmically from 0.00270 ml to 0.01180 ml across valve settings. In additional tests, drug-experienced rats were tested with either 5.0 microgram/ml etonitazene HCl, water, or 8% w/v ethanol available with the valve at its widest setting. More of the drug solutions were consumed than water suggesting that the drugs served as reinforcers. Intakes of both drugs were compared with intakes previously determined in dipper delivery systems using the same rats. This liquid delivery system has several advantageous features in that it is inexpensive to construct, allows quick and easy control of the volume delivered, minimizes evaporation, and, along with the heterogenous chain schedule of reinforcement, insures that liquid is delivered only when oral contact is made with it.

Alcohol Drinking↗
PubMed1979

Food deprivation increases oral and intravenous drug intake in rats.

Rats given continuous access to etonitazene hydrochloride in their drinking water (5 micrograms per milliliter) more than doubled their drug intake while deprived of food. Another group of rats with implanted jugular catheters self-administered etonitazene (10 micrograms per kilogram) intravenously on a continuous reinforcement schedule, and the number of infusions increased significantly on days when they were deprived of food. These results suggest that feeding condition may be a powerful determinant of drug-reinforced behavior.

Administration, Oral↗
PubMed1979

Effects of food deprivation on etonitazene consumption in rats.

One group of free-feeding rats was given a 5 microgram/ml etonitazene HCl solution as their sole liquid. This group increased their drug intake by 100% when they were partially food-deprived during a 23-day period. Another group that remained food-satiated and received etonitazene for an equal number of days did not show similar increases in drug intake. However, this group drank greater volumes of the etonitazene solution than a food-satiated control group drank of water. These results are contrasted with a fourth group showing a 50% decrement in water intake during similar food-deprived conditions. The food-deprived group drinking etonitazene showed highly erratic drinking patterns compared to all the other groups. Daily liquid intake ranged from 30 to 250 ml in this group, and volumes oscillated from high to low on alternating days. When the food-deprived/food-satiated conditions were replicated in this experimental group, corresponding increases and decreases in drinking reliably occurred. However, during the second food-deprived phase, the large increases occurred almost immediately as contrasted with a gradual increase over 17 days during the first food-deprived phase. This would suggest a learning mechanism may be involved. Self-mutilation and other forms of stereotypy were noted only in food-deprived rats consuming etonitazene.

Animals↗
PubMed1979

Ethanol drinking by rhesus monkeys with concurrent access to water.

Three monkeys were provided concurrent access to water and ethanol in concentrations of either 8, 16 or 32% (w/v) during daily 3-hr sessions. The monkeys were those for whom ethanol had been established as a reinforcer in an earlier study in which only ethanol or water was available. Ethanol was preferred to water at all concentrations and volume of ethanol consumed was inversely related to ethanol concentration. Quantity of ethanol (g/kg of body wt.) consumed remained relatively constant, and blood ethanol determinations confirmed that the monkeys were drinking ethanol. Water drinking occurred at negligible levels except by one monkey at 16 and 32% who followed ethanol drinking bouts by water bouts (chasers) in a manner similar to that reported in other studies. Two monkeys were also provided concurrent access to 8% ethanol and water during 23-hr daily sessions. Under these conditions, ethanol was consumed every few hours to the near exclusion of water. The significance of this study lies largely in its procedure; that is, the development and application of a concurrent water-ethanol preparation in which ethanol serves as a reinforcer for rhesus monkeys. This preparation should be useful in the evaluation of a wide range of factors suspected to control alcoholic drinking.

Alcohol Drinking↗
PubMed1978

Etonitazene as a reinforcer: oral intake of etonitazene by rhesus monkeys.

Drinking of etonitazene HCI was studied in three rhesus monkeys during daily 3-h sessions. As the drug concentration was increased, the number of liquid deliveries decreased, and etonitazene intake (microgram/kg body weight) increased. As fixed-ratio (FR) requirements were increased, rate of responding increased, and liquid deliveries slightly decreased. When water was substituted for the drug, there was a large increase in responding for several sessions, followed by a slow decline to low rates. When etonitazene was reintroduced, responding abruptly increased to previous drug levels. These data suggest that etonitazene can serve as a positive reinforcer when taken orally by rhesus monkeys.

Animals↗
PubMed1978

Ethanol-reinforced behavior of rats with concurrent access to food and water.

Dippers filled with water or an ethanol solution were presented to male Wistar rats contingent on lever-pressing under a concurrent fixed-ratio 1 (water) fixed-ratio 1 (ethanol) schedule. During Phase I, when maintenance feedings were given during instead of following the daily 3-h sessions, the feedings increased drinking of both 8% (w/v) ethanol and water, with 8% ethanol being consumed in greater volumes than water. In Phase II, a 28-day transitional period from the food-deprived to the food-satiated state, continuous access to food during 3-h sessions moderately decreased 8% ethanol intake, and increased water intake and total liquid intake (water plus 8% ethanol). In Phase III, concurrent water and ethanol intake of food-satiated rats was compared over two identical series of ethanol concentrations (8, 11.3, 16, 22.6, 32, and 8% retest). Food was freely available in both the operant conditioning chambers and home cages. The number of dipper presentations of ethanol exceeded presentations of water for each rat at each concentration studied. Presentations of water were low in number and did not vary with the ethanol concentration. As the ethanol concentration was increased, the number of ethanol presentations decreased, while the quantity consumed (mg/100 g body weight/h) generally increased.

Animals↗
PubMed1978

Ethanol drinking by rhesus monkeys as a function of concentration.

Ethanol deliveries maintained fixed-ratio (FR) responding of three rhesus monkeys during daily 3-h sessions. At FR values of 8 or 16, ethanol concentration was varied in the sequence 0 (water), 8, 11.3, 16, 22.6 32, 8, and 0% (w/v). As the ethanol concentration increased, number of liquid deliveries decreased somewhat. Blood ethanol levels were usually greater than 200 mg% and occasionally greater than 300 mg%.

Alcohol Drinking↗