In this experiment, we tested for opioid and nonopioid mechanisms of pain control through cognitive means and the relation of opioid involvement to perceived coping efficacy. Subjects were taught cognitive methods of pain control, were administered a placebo, or received no intervention. Their pain tolerance was then measured at periodic intervals after they were administered either a saline so...

Research on the mode of action of narcotic analgesic drugs and the mechanism of the development of tolerance and physical dependence is one of the oldest of scientific pursuits. For many years the first step in the action of these drugs was postulated to be their binding to highly specific "receptor" sites. This specific drug-receptor interaction was thought to trigger certain chemical or physi...

Distribution and Metabolism of Mescaline-C’4 in the Cat Brain. N. NEFF, G. V. ROSSI, G. D. CHASE AND J. L. RABINOWITZ 1 Use of Hindlimb Reflexes of the Chronic Spinal Dog for Comparing Analgesics. W. R. MARTIN, C. G. EADES, H. F. FRASER AND A. WIKLER 8 The Analgesic Efficacy and Respiratory Effects in Man of a Benzomorphan “Narcotic Antagonist.” LOUIS LASAGNA, THOMAS J. DE KORNFELD AND JOHN W. ...

We hypothesized that the opioid antagonist naltrexone would inhibit the redevelopment of a preference for a high-sucrose diet after an abstention period from this diet. Rats that chose between a starch or sucrose diet for 10 days preferred the sucrose diet. Rats were then given access to the starch diet alone for another 10-day period. A miniosmotic pump containing saline or naltrexone was then...

We hypothesized that interference of opiate antagonist-precipitated withdrawal signs under anesthesia is anesthetic-specific. Three groups of morphine-dependent rats were compared in different experimental conditions using a protocol of rapid withdrawal induction by an antagonist under anesthesia. We observed that ketamine and midazolam have different effects on the expression of withdrawal. Th...

We tested the hypothesis that thermal tail-flick latency, a common measure of pain sensitivity in rodents, would be altered in lines of mice that had been selectively bred for high voluntary wheel-running behavior. Specifically, we predicted that the selected (High-Runner) lines would show decreased pain sensitivity relative to their control (C; randombred) lines, and would respond differently ...

BACKGROUND AND OBJECTIVES Pre-clinical and clinical trials of peripheral opiate antagonists have shed new light on the effects of exogenous and endogenous opioids. CONTENTS This article review preclinical studies and clinical opioid bowel disfunction trials. CONCLUSIONS If approved these drugs may offer potential solutions to important clinical problems in pain management.

The endogenous opioid system represents one of the principal systems in the modulation of pain. This has been demonstrated in studies of placebo analgesia and stress-induced analgesia, where anti-nociceptive activity triggered by pain itself or by cognitive states is blocked by opioid antagonists. The aim of this study was to characterize the effect of opioid receptor blockade on the physiologi...

Painful stimuli are known to engage an endorphin analgesic system that can be reversed by the opiate antagonist, naloxone. Naloxone, then, should increase the effectiveness of aversive unconditioned stimuli (USs) in Pavlovian fear conditioning. Consistent with this hypothesis, naloxone administered during the acquisition of conditioned suppression in rats enhanced posttrial suppression and prec...