Heart rate conditioning with pentobarbital as a conditioned stimulus and amphetamine as an unconditioned stimulus.

Abstract

Pentobarbital was injected into rats 20 min after they were placed in an apparatus where heart rates were recorded. Amphetamine was injected after they were removed from the apparatus 29-30 min later. A Pavlovian conditioned response (CR) began after three or four such trials in the form of a failure of conditioned rats to show the same decline in heart rate obtained in controls after the pentobarbital injection. On later trials, the amphetamine was not injected until 50 min after the pentobarbital, and the CR was most obvious during the period 30-50 min after the pentobarbital injection, an effect characteristic of Pavlovian delay conditioning. The pharmacological effects of pentobarbital were necessary for conditioning because the CR was not obtained (a) when normal saline was substituted for the pentobarbital after successful conditioning or (b) when saline was used instead of pentobarbital throughout. Because of the speed and effectiveness of the conditioning, we believe the mechanism responsible for it has homeostatic regulation as its natural role. It was puzzling that environmental cues seemed to have a role in the conditioned stimulus complex, because conditioning was not apparent when the drug-drug pairings were administered in the home cage.

Extending the Role of Associative Learning Processes in Nicotine Addiction

“…However, recent research from our laboratory with nicotine (Besheer, Palmatier, Metschke, & Bevins, 2004;Palmatier, Peterson, Wilkinson, & Bevins, 2004;Sanderson et al, 2003) and other laboratories with ethanol, morphine, diazepam, or pentobarbital (Alessi, Roll, Reilly, & Johanson, 2002;Greeley, Lê, Poulos, & Cappell, 1984;Kim, Siegel, & Patenall, 1999;Revusky, Davey, & Zagorski, 1989) suggest that this focused conceptualization of nicotine might not completely capture the complexity of the associative processes involving nicotine and, by theoretical extension, the associative factors contributing to tobacco dependence. We suggest that a more complete associative analysis of nicotine dependence will also include nicotine in the role of a CS.…”

“…Relative to controls that received similar exposure to the drugs in an unpaired fashion, the pentobarbital CS came to evoke an increase in heart rate. Acquisition of the heart rate CR was sensitive to CS salience and the nature of the US, and once acquired, the CR survived a 43-day retention interval (Reilly & Revusky, 1992;Revusky et al, 1989;Revusky & Reilly, 1990). An interesting variant of this drug-drug conditioning protocol uses a low dose of a drug as a CS for a later and typically larger eff ect of the same drug (US).…”

“…More important, drugdrug conditioning research indicates that the pharmacological eff ects of a drug can serve as a CS for the pharmacological eff ects of another drug. For example, Revusky et al (1989) paired pentobarbital (32 mg/kg) repeatedly with amphetamine (24 mg/kg) in rats. Pentobarbital, the putative CS, was administered 30 minutes before amphetamine, the putative US.…”

Nicotine as a signal for the presence or absence of sucrose reward: a Pavlovian drug appetitive conditioning preparation in rats

“…For example, Revusky et al (1989) gave rats repeated exposure to pentobarbital (32 mg/kg) 30 min before d-amphetamine (24 mg/kg). Pentobarbital was conceptualized as the CS and amphetamine as the US.…”

Classical conditioning in humans: nicotine as CS and alcohol as US

“…Cook et al, 1960;Turner and Altshuler, 1976;Bormann and Overton, 1993;Overton et al, 1993) and a small number of animal studies have provided evidence that one drug can come to act as a conditioned stimulus signalling the administration of another (e.g. Greeley et al, 1984;Revusky et al, 1989;Takulis and Brake, 1989;Silverman, 1990;Carey, 1991).…”