Physiology & behavior
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Physiology & behavior · Mar 2017
Pain modulation as a function of hypnotizability: Diffuse noxious inhibitory control induced by cold pressor test vs explicit suggestions of analgesia.
The aim of the present study was to compare the effects of explicit suggestions of analgesia and of the activation of the Diffuse Noxious Inhibitory Control (DNIC) by cold pressor test on pain perception and heart rate in healthy participants with high (highs, N=18), low (lows, N=18) and intermediate scores of hypnotizability (mediums, N=15) out of hypnosis. Pain reports and the stimulus-locked heart rate changes induced by electrical nociceptive stimulation of the left hand were studied in the absence of concomitant stimuli (Control), during suggestions of analgesia (SUGG, glove analgesia) and during cold pressor test used as a conditioning stimulus to the right hand (DNIC, water temperature=10-12°C) in the REAL session. ⋯ Heart rate was not modulated consistently with pain experience. Findings indicate that both suggestions and DNIC influence pain experience as a function of hypnotizability and suggest that both sensory and cognitive mechanisms co-operate in DNIC induced analgesia.
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Physiology & behavior · Mar 2017
Circulating levels of endocannabinoids respond acutely to voluntary exercise, are altered in mice selectively bred for high voluntary wheel running, and differ between the sexes.
The endocannabinoid system serves many physiological roles, including in the regulation of energy balance, food reward, and voluntary locomotion. Signaling at the cannabinoid type 1 receptor has been specifically implicated in motivation for rodent voluntary exercise on wheels. We studied four replicate lines of high runner (HR) mice that have been selectively bred for 81 generations based on average number of wheel revolutions on days five and six of a six-day period of wheel access. ⋯ In addition, females tended to have higher AEA concentrations than males. For mice housed with wheels, the amount of running during the 30min before sampling was a significant positive predictor of plasma AEA within groups, and HR mice had significantly lower levels of AEA than C mice. Our results suggest that voluntary exercise alters circulating levels of endocannabinoids, and further demonstrate that selective breeding for voluntary exercise is associated with evolutionary changes in the endocannabinoid system.
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Physiology & behavior · Feb 2017
Apnea-hypopnea index prediction through an assessment of autonomic influence on heart rate in wakefulness.
With the high prevalence of obstructive sleep apnea, the issue of developing a practical tool for obstructive sleep apnea screening has been raised. Conventional obstructive sleep apnea screening tools are limited in their ability to help clinicians make rational decisions due to their inability to predict the apnea-hypopnea index. Our study aimed to develop a new prediction model that can provide a reliable apnea-hypopnea index value during wakefulness. ⋯ Using the predictors obtained from 184 individuals, regression analyses and k-fold cross-validation tests were performed to develop an apnea-hypopnea index prediction model. For the remaining 92 individuals, the developed model provided an absolute error (mean±SD) of 3.53±2.67events/h and a Pearson's correlation coefficient of 0.99 (P<0.01) between the apnea-hypopnea index predictive values and the reference values reported by polysomnography. Our study is the first to achieve reliable and time-efficient prediction of the apnea-hypopnea index during wakefulness.
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Physiology & behavior · Feb 2017
Behavioral changes in male mice fed a high-fat diet are associated with IL-1β expression in specific brain regions.
High-fat diet (HFD)-induced obesity is associated with not only increased risk of metabolic and cardiovascular diseases, but cognitive deficit, depression and anxiety disorders. Obesity also leads to low-grade peripheral inflammation, which plays a major role in the development of metabolic alterations. Previous studies suggest that obesity-associated central inflammation may underlie the development of neuropsychiatric deficits, but further research is needed to clarify this relationship. ⋯ However, we observed no association between depressive-like behavior and IL-1β expression in any of the brain regions investigated. Together our data provide evidence that mice fed a HFD exhibit cognitive deficits, anxiety and depressive-like behaviors. Our results also suggest that increased expression of IL-1β in the hippocampus and amygdala may be associated with the development of cognitive deficits and anxiety-like behavior, respectively.
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Postoperative sleep disorders, particularly the REM sleep disorder, may have a significant deleterious impact on postoperative outcomes and may contribute to the genesis of certain delayed postoperative complications. We have followed the effect of distinct anesthesia regimens (ketamine/diazepam vs. pentobarbital) over 6days following the induction of a stable anesthetized state in adult male Wistar rats, chronically instrumented for sleep recording. In order to compare the effect of both anesthetics in the physiological controls vs. the rats with impaired pedunculopontine tegmental nucleus (PPT) cholinergic innervation, during the operative procedure for the implantation of EEG and EMG electrodes, the bilateral PPT lesion was conducted using ibotenic acid (IBO). ⋯ On the other hand, whereas both anesthetic regimens abolished the prolonged post-anesthesia REM/REM1 sleep and the EEG microstructure disorder during REM sleep, only the pentobarbital abolished the increased NREM/REM/NREM transitions, caused by the PPT lesion. In addition, in the PPT lesioned rats, the ketamine/diazepam anesthesia decreased the Wake/NREM/Wake transitions while the pentobarbital anesthesia decreased the Wake/REM/Wake transitions. Our present study suggests pentobarbital anesthesia as being highly beneficial for post-anesthesia REM sleep in the physiological condition as well as during PPT cholinergic neuropathology.