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Biomedical subjects

R A Meisch

Publications and source records attributed to R A Meisch.

At least 91 records · Page 5Linked to original sources
PubMed1977

Establishment of etonitazene as a reinforcer for rats by use of schedule-induced drinking.

Drinking of etonitazene HCl by 6 rats was studied during daily 4-hr sessions. Five related experiments were conducted sequentially. In the first experiment schedule-induced polydipsia was established. Subsequently, etonitazene concentrations (1.25, 2.5 and 5.0 microgram/ml) were substituted for water, and intake of large quantities of the drug occurred. In the second experiment the concurrent food reinforcement schedule was discontinued and lever presses maintained by etonitazene (5 microgram/ml) persisted. In the third experiment the number of lever presses, required per dipper presentation of etonitazene (5 microgram/ml) was increased, and rate of lever pressing increased directly with the response requirement whereas number of dipper presentations remained constant. In the fourth experiment water was substituted for the 5 microgram/ml etonitazene solution. Water responding declined to low rates, but when etonitazene was reintroduced, responding increased to previous levels. Thus, etonitazene (5 microgram/ml) was functioning as a positive reinforcer. In the final experiment, progressive increases in the etonitazene concentration (5, 10, 20 and 40 microgram/ml) resulted in both systematic decreases in response rate and increases in quantity (microgram) consumed.

Animals↗
PubMed1977

Ketamine self-administration by the rhesus monkey.

Intravenously administered ketamine served as a reinforcer of self-administration behavior in rhesus monkeys during daily 2-hour sessions. When the dose of ketamine was varied over a wide range at fixed-ratio schedules of reinforcement of 1, 8 and 64, the response rate was an inverted U-shaped function of the dose. Maximal response rates occurred at progressively higher doses as the fixed-ratio size was increased; drug intake per session was positively related to the dose. When the ketamine dose was held constant and the fixed-ratio was increased in a geometric series, the response rate increased as the fixed-ratio was increased to FR 128 or FR 256; additional increases in fixed-ratio size produced abrupt decreases in response rates. Since the response rate increased linearly as the fixed-ratio was increased geometrically, drug intake was a decreasing function of the response requirement. With respect to magnitude of reinforcement and fixed-ratio response requirement, the data show that ketamine maintains self-administration behavior in a manner similar to that of a number of other drugs and conventional reinforcers.

Animals↗
PubMed1976

Ethanol as a positive reinforcer via the oral route for rhesus monkeys: maintenance of fixed-ratio responding.

Two rhesus monkeys were required to emit 1 to 16 responses (FR 1, 2, 4, 8, and 16) per 0.5 ml delivery of either 8% (w/v( ethanol or water. Ethanol had been established as an effective reinforcer via the oral route in an earlier experiment [4]. At FR 16, responding maintained by ethanol clearly exceeded responding maintained by water for both monkeys. The volume of ethanol intake per session remained nearly constant from FR 1 to FR 16, however, the volume of water consumed per session decreased when FR 16 was required.

Animals↗
PubMed1976

Drinking device for rhesus monkeys.

A drinking device for rhesus monkeys is described which is simple, reliable, and permits intermittent scheduling of liquid availability. The device may be of particular use in oral drug self-administration experiments since the amount of fluid dispensed may be calibrated and spillage is minimals. The system has been successfully used for over 3 years with 9 unrestrained rhesus monkeys.

Animals↗
PubMed1975

Ethanol as a reinforcer for rats: effects of concurrent access to water and alternate positions of water and ethanol.

Water and ethanol solutions were concurrently made available on a continuous reinforcement schedule to 4 food-deprived male albino rats during daily 1-hr sessions in an operant conditioning chamber equipped with 2 levers and 2 liquid dippers. The number of ethanol reinforcements substantially exceeded the number of water reinforcements for each rat at each concentration studied (8, 16, and 32% w/v). Water reinforcements were low in number and did not vary with ethanol concentration. As the ethanol concentration was increased, the number of ethanol reinforcements obtained decreased, while the quantity consumed (mg/100 g of body weight/hr) increased. The highest rate of responding occurred at the beginning of the session.

Alcohol Drinking↗
PubMedDate not supplied

Ethanol-reinforced responding and intake as a function of volume per reinforcement.

Number of ethanol reinforcements obtained and ethanol intake (mg/100 g body weight/hr) of 3 food-deprived rats were measured over a range of dipper volumes during daily 1 hr sessions. The rats had free access to water in their home cages between sessions. Ethanol concentration was 8 percent (W/V); each response was reinforced. As the volume per reinforcement increased, ethanol intake tended to increase while the number of reinforcements obtained decreased systematically. Responding was maintained by 8 percent (W/V) ethanol but not by water.

Alcohol Drinking↗
PubMedDate not supplied

Differential concentration-response curves for oral ethanol self-administration in C57BL/6J and BALB/cJ mice.

In an earlier study ethanol drinking was induced by reducing mice to 80% of their free-feeding weight and feeding them their daily food allotment prior to the experimental session. The mice were given an ascending series of ethanol concentrations (1 to 8%). The inducing condition was subsequently eliminated to determine if the drinking of 8% ethanol would persist in its absence. Eight percent ethanol served as a reinforcer for the C57BL/6J mice but not for the BALB/cJ mice. The purpose of the present study was to examine strain differences in ethanol maintained behavior over a range of concentrations from 1 to 32% (w/v). Ethanol served as a reinforcer for the C57BL/6J mice at concentrations of 4, 8 and 16%. Lever presses and volume of liquid consumed per unit of body weight were inverted U-shaped functions of ethanol concentration. Post-session blood ethanol levels confirmed intake of pharmacologically significant amounts of ethanol. Results with the BALB/cJ mice were very different from those with the C57BL/6J mice. The level of responding did not increase above baseline levels at any of the concentrations tested, and levels of responding decreased below baseline at 32%. Thus, ethanol did not serve as a reinforcer for the BALB/cJ mice at any of the concentrations tested. These results demonstrate that over a range of ethanol concentrations genotype is an important determinant of ethanol reinforced behavior.

Alcohol Drinking↗