Discrete-trial control of morphine self-injection behaviour in monkeys: effects of injection dose and trials per session

1977 ◽  
Vol 55 (1) ◽  
pp. 121-125 ◽  
Author(s):  
Roger Stretch ◽  
Gary J. Gerber
Keyword(s):  
Response Probability ◽  
Control Procedure ◽  
Significant Delay ◽  
Self Administration ◽  
Discrete Trials ◽  
Intravenous Injections ◽  
Trial Spacing ◽  
Injection Dose ◽  
Primary Determinant ◽  
Inter Trial Interval

Responding for intravenous injections of morphine was studied using a discrete-trials procedure in squirrel monkeys. For one group, each session consisted of 10 trials at an inter-trial interval of 15 min; for the second group, each session consisted of 100 trials at an inter-trial interval of 1.5 min. When different injection doses of morphine (1–1000 μg/kg per injection), including saline as a control procedure, were substituted at random for blocks of five consecutive sessions, the frequency of morphine self-administration was found to be an inverted U-shaped function of the injection dose. This relationship was observed in each group of monkeys, despite a 10-fold difference in the total amount of the drug which was available for self-administration per session when a given injection dose was substituted for both groups. The results show that the injection dose of morphine acted as a primary determinant of response probability, even under circumstances in which trial spacing imposed a significant delay between consecutive opportunities for drug self-administration.

Discrete-trial control of morphine self-injection behaviour in squirrel monkeys: effects of naloxone, morphine, and chlorpromazine

1977 ◽  
Vol 55 (3) ◽  
pp. 615-627 ◽  
Author(s):  
Roger Stretch
Keyword(s):  
Daily Basis ◽  
Self Administration ◽  
Small Unit ◽  
Discrete Trials ◽  
Time Out ◽  
Intravenous Morphine ◽  
Inter Trial Interval ◽  
Unit Dose ◽  
Response Output ◽  
Withdrawal Signs

Intravenous morphine self-injection behaviour was studied using a new discrete-trials procedure in monkeys. Morphine self-injection was most probable when small unit doses (10–100 μg/kg per injection) were available and least frequent, even in comparison with saline substitution, at doses of 300 and 400 μg/kg per injection. Despite variation of the inter-trial interval from 50 to 300 s small injection doses (25 and 100 μg/kg per injection) continued to sustain more frequent self-injection responding than a larger unit dose (400 μg/kg per injection). When daily sessions consisted of 40 trials at an inter-trial interval of 50 s, morphine self-injection behaviour (100 μg/kg per injection) was neither increased nor consistently decreased by naloxone pretreatment (0.1–1.0 mg/kg im). In subsequent experiments, daily sessions consisted of two sets of 40 discrete trials, separated by a time-out (TO) period. When monkeys were pretreated with morphine (5.6 mg/kg im) before a given session, responding for drug injections was suppressed; the effect was reversed by naloxone (1 mg/kg im) which, if injected at TO, reinstated morphine self-administration behaviour. When an injection of chlorpromazine (5.6 mg/kg im) preceded a given session, responding for morphine injections was also suppressed; naloxone (1 mg/kg im) failed to reinstate chlorpromazine-suppressed responding, indicating that naloxone acted as an acute morphine antagonist under some circumstances, but did not otherwise influence behaviour. When the unit dose of morphine was increased to 200 μg/kg per injection, naloxone (1–3 mg/kg im) elicited agitation and occasional vomiting in each monkey tested, but did not suppress their drug-taking behaviour. Though small increases in morphine intake were observed after naloxone pretreatment, substantial increases in response output during the inter-trial interval, with a consequent loss of stimulus control normally exerted by the trial signal, were observed. These results were interpreted in terms of acute, antagonist-precipitated withdrawal signs, not evident in response to naloxone pretreatment when drug self-injection responding was maintained on a daily basis by a limited number of smaller unit injection doses of morphine (50 or 100 μg/kg per injection).

Discrete-trials heroin self-administration produces sensitization to the reinforcing effects of cocaine in rats

2006 ◽  
Vol 185 (2) ◽  
pp. 150-159 ◽  
Author(s):  
Sara J. Ward ◽  
Christopher Läck ◽  
Drake Morgan ◽  
David C. S. Roberts
Keyword(s):  
Self Administration ◽  
Discrete Trials ◽  
Reinforcing Effects

scholarly journals Comparison of the Relative Abuse Liability of Electronic Cigarette Aerosol Extracts and Nicotine Alone in Adolescent Rats: A Behavioral Economic Analysis

2020 ◽  
Vol 17 (3) ◽  
pp. 860
Author(s):  
Andrew C. Harris ◽  
John R. Smethells ◽  
Mary Palumbo ◽  
Maciej Goniewicz ◽  
Mark G. LeSage
Keyword(s):  
Electronic Cigarettes ◽  
The United States ◽  
Abuse Liability ◽  
Self Administration ◽  
Behavioral Economic ◽  
Product Regulation ◽  
Primary Determinant ◽  
United States Food ◽  
The Central Nervous System ◽  
Adolescent Rats

Background: Characterizing the determinants of the abuse liability of electronic cigarettes (ECs) in adolescents is needed to inform product regulation by the United States Food and Drug Administration (FDA). We recently reported that Vuse Menthol EC aerosol extract containing nicotine and a range of non-nicotine constituents (e.g., menthol, propylene glycol) had reduced aversive effects compared to nicotine alone in adolescent rats, whereas Aroma E-Juice EC aerosol extract did not. The current study used a behavioral economic approach to compare the relative abuse liability of these EC extracts and nicotine alone in an i.v. self-administration (SA) model in adolescents. Methods: Adolescents were tested for the SA of EC extracts prepared using an ethanol (ETOH) solvent or nicotine and saline, with and without 4% ETOH (i.e., the same concentration in the EC extracts) in 23 h/day sessions. Results. Although acquisition of SA was faster for nicotine + ETOH compared to all other formulations, the elasticity of demand for all nicotine-containing formulations was similar. Conclusions: EC aerosol extracts did not have greater abuse liability than nicotine alone in adolescents. These data suggest that nicotine may be the primary determinant of the abuse liability of these ECs in youth, at least in terms of the primary reinforcing effects of ECs mediated within the central nervous system.

Recall of Initial Response, Probability Scale Meaning, and the Group-Shift Effect

1976 ◽  
Vol 39 (3_suppl) ◽  
pp. 1271-1278 ◽  
Author(s):  
Marsha B. Jacobson ◽  
James S. Uleman
Keyword(s):  
Response Probability ◽  
Initial Response ◽  
Control Procedure ◽  
Comparison Process ◽  
Probability Scale ◽  
Male And Female ◽  
Ego Ideal ◽  
Shift Effect ◽  
Group Shift ◽  
Social Comparison Process

The results of three studies are reported in which male and female subjects responded to risk and caution life-dilemma problems in either a standard discussion or a control procedure. Exp. 1 showed that subjects' recall of their initial positions shifted to match their final positions but only on risk dilemmas. Exp. 2 reconstructed subjects' recall of their initial positions from their perceived shift and found that subjects' reconstructed recall shifted toward their final positions for both dilemma types but more so on risk dilemmas. Exp. 3 found that subjects changed the meaning of the probability scale on risk dilemmas only. Taken together, the results are interpreted to mean that the value of risk is an ego-ideal, since subjects apparently wish to view themselves as having been consistently risky but that shifts to caution are brought about through some sort of social-comparison process.

Discrete-trial control of cocaine self-injection behaviour in squirrel monkeys: effects of morphine, naloxone, and chlorpromazine

1977 ◽  
Vol 55 (4) ◽  
pp. 778-790 ◽  
Author(s):  
Roger Stretch
Keyword(s):  
Fixed Ratio ◽  
Relative Sensitivity ◽  
Suppressive Effect ◽  
Dependent Manner ◽  
Self Administration ◽  
Drug Reinforcement ◽  
Discrete Trials ◽  
Small Doses ◽  
Large Injection ◽  
Unit Dose

Intravenous cocaine self-injection behaviour was studied using a new discrete-trials procedure in monkeys. Daily sessions consisted of two sets of 40 discrete trials, separated by a 5-min time out (TO) period; the intertrial interval during each segment of the session was equal to 50 s. In the first experiment, cocaine self-injection behaviour (15 μg/kg per injection) was suppressed in a dose-dependent manner by morphine pretreatment (1–5.6 mg/kg, im). When cocaine self-injection responding was suppressed by morphine pretreatment (3 or 5.6 mg/kg, im), the morphine antagonist, naloxone (0.01–1.0 mg/kg, im), reinstated drug-taking behaviour; the effect depended upon the dose of the antagonist and upon the amount of morphine given to suppress cocaine self-administration behaviour. When monkeys were pretreated with chlorpromazine (0.03–5.6 mg/kg, im) before a cocaine self-injection session, small doses marginally increased responding and larger doses exerted a suppressive effect. These effects were observed when cocaine was available at a unit dose of 15 μg/kg per injection. When the unit dose of cocaine was increased to 300 μg/kg per injection, small doses of chlorpromazine (0.03–1 mg/kg, im) exerted no clearly detectable effects, though responding for drug injections was profoundly suppressed when sessions were preceded by chlorpromazine pretreatment at doses of 3 and 5.6 mg/kg, im. In this experiment, drug intake per session was greater when a large injection dose (300 μg/kg per injection) was available for self-administration than when a small dose (15 μg/kg per injection) could be self-injected; the frequency of drug self-injection was reduced, however, when the larger unit dose of cocaine replaced the smaller one. When considered in relation to the results of other experiments, it is evident that control of cocaine self-injection responding by a discrete-trials procedure results in schedule-dependent behaviours that differ in relative sensitivity to drug pretreatments from cocaine-reinforced responding controlled by fixed-ratio schedules of drug reinforcement.

Patterns of cocaine self-administration in rats produced by various access conditions under a discrete trials procedure

2002 ◽  
Vol 67 (3) ◽  
pp. 291-299 ◽  
Author(s):  
David C.S Roberts ◽  
Karen Brebner ◽  
Michelle Vincler ◽  
Wendy J Lynch
Keyword(s):  
Self Administration ◽  
Discrete Trials
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