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Biomedical subjects

G Singer

Publications and source records attributed to G Singer.

13 recordsLinked to original sources
PubMed1979

Hypnotic analgesia in conditions of stress is partially reversed by naloxone.

In this study the hypothesis that hypnotic analgesia under conditions of stress is mediated through a neurochemical mechanism involving the release of opioid peptides in the CNS was investigated. Ten highly hypnotizable subjects participated in a 2 x 2 factorial design, which involved hypnotic analgesia, stress and double blind administration of naloxone (an opiate antagonist) or placebo. Analysis of post-hypnosis results indicates that hypnotic analgesia was significantly reversed by the interactive effects of stress and naloxone. It is inferred that stress may be the common psychological denominator of the various analgesic methods which effectively engage this endogenous pain inhibitory system. Additional analyses of anxiety measures reveals no significant association between trait and state anxiety, but significant relationships between state anxiety and time tolerance to ischemic pain. These results suggest that anxiety remains a definitional problem and that previous conceptualizations may not have satisfactorily explained the affect's adaptive function.

Adult↗
PubMed1979

Interactions between personal expectations and naloxone: effects on tolerance to ischemic pain.

Sixteen healthy subjects participated in an investigation of the interactive effects of naloxone and personal expectations of control, stress, and anxiety, on time tolerance to ischemic pain. Control and anxiety levels provided no significant naloxone-saline discriminations, but there was a significant interaction between stress levels and naloxone-induced reduction in tolerance to ischemia. This finding suggests that activity in the opiate system may be a function of the modifying influences of variable attitudes to environmental stress. A primary analgesic role for the endorphins is challenged, however, by the findings that tolerance levels failed to reveal naloxone reactors and stress levels were not significantly associated with differences in tolerance. The latter, on the other hand, correlated significantly with control and anxiety levels, indicating that further research is needed to clarify the complex relationship between these three variables and their effects on the modulation of pain perception.

Adult↗
PubMed1979

The involvement of interoceptive factors in the maintenance of heroin-seeking behavior.

The role of interoceptive stimuli in conditioned heroin-seeking behavior was investigated using forty-two naive male Wistar rats. A 21-day Phase I period in which 28 animals self-injected heroin in saline solution was followed by a 5-day Phase II period in which 7 animals were allowed access to the original solution; 7 animals were allowed access to saline only; 7 animals were allowed access to distilled water; and 7 animals were allowed no access to any solution. Results showed that only the heroin and (heroin-associated) saline groups shows a significant difference in operant rate compared to animals that had been continually exposed to saline only. It was concluded that heroin-seeking behavior was maintained in the (heroin-associated) saline group as a result of physiological conditioning following repeated association of saline with heroin.

Animals↗
PubMed1979

Self-administration of delta 9-tetrahydrocannabinol by rats.

The present study examines the dose-response pattern of delta 9-tetrahydrocannabinol self-injection in naive rats at 80% reduced body weight and 100% body weight, both conditions with a fixed-time 1 min (FT-1) food delivery schedule. The results indicated that food deprived animals tested on a FT-1 min schedule self-injected low doses of delta 9-THC at a higher rate than those animals at 100% body weight and on a FT-1 min schedule. Animals at 80% reduced body weight without a schedule did not differ from rats self-injecting delta 9-THC at free feeding situation. These findings suggest that rats without previous history of drug dependence self-administer low doses of delta 9-THC and that the interaction between the food deprivation state and the environmental contingencies introduced by a FT-1 min schedule is a critical variable in the acquisition period.

Animals↗
PubMed1979

Effects of a fixed time schedule and body weight on ethanol self-administration.

Two experiments are reported. The first study showed that the patterns of ethanol acquisition using the schedule induced self-injection paradigm, are more similar to those of heroin than methadone or nicotine but dissimilar to that of d-amphetamine. The second study showed that ethanol intake once established was not maintained by removal of the schedule. The results also showed that schedule induced behavior may be stressful as indexed by a significant increase of plasma corticosterone levels.

Alcohol Drinking↗
PubMed1978

Schedule induced self injections of nicotine with recovered body weight.

In a recent series of experiments we have shown that high rates of self injection of nicotine were acquired when rats are at 80% body weight on an FT-1 min food delivery schedule. This rate was significantly higher than that of rats at reduced or normal body weight without food delivery schedules or that of rats injecting saline under three parallel control conditions. In the present experiment naive rats were trained to acquire nicotine self injection at 80% body weight with an FT-1 min food delivery schedule. These rats maintained their self injection rates after they were allowed to regain free feeding body weight. The data indicate that once nicotine intake behavior is established it can be maintained with changing nutritional factors.

Animals↗
PubMed1978

The effect of EMG biofeedback on postoperative pain following abdominal surgery.

To investigate the effects of electromyography (EMG)-biofeedback on pain experienced during the immediate post-operative period following abdominal surgery, twelve patients were randomly assigned to either (1) EMG-biofeedback from abdominal muscles; (2) EMG-biofeedback from the frontalis muscles; or (3) were given no EMG treatment. EMG training consisted on one pre-operative 30 minute session, and three 30 minute postoperative sessions. All patients were able to reduce EMG activity. A within-sessions analysis of pain reports (on a 0-10 pain intensity scale) indicated that EMG biofeedback is an effective method of pain relief only when feedback is given to the muscle site involved in the operation.

Abdomen↗
PubMedDate not supplied

Biochemical and pharmacological basis for the lateral hypothalamic syndrome.

The lateral hypothalamic (LH) syndrome characterized by impairment of the ability to regulate food and water intake has been reported to occur after injections of 6-hydroxydopamine (6-OHDA) into this region. In the present experiment the fluorescence histochemical technique was used to assess monoamine depletion of noradrenaline and dopamine containing neurons following intrahypothalamic injection of 6-OHDA. Results show that the intensity and area of monoamine accumulation in axons served by 6-OHDA is correlated with the severity of behavioral deficits but that actual catecholamine depletion of either the corpus striatum or the hypothalamus is unrelated to the syndrome. Possible mechanisms of action of this accumulation in producing behavioral deficits are discussed.

Animals↗