Autonomic neuroscience : basic & clinical
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Sympathetic overactivation is suggested to be associated with chronic pain syndrome, and acupuncture is frequently applied in therapy for this syndrome. Furthermore, the forebrain including the various cerebral cortices has been implicated in inhibitory and facilitatory control of pain as well as autonomic functions. We investigated relationships among specific sensations induced by acupuncture manipulation, effects on sympathetic and parasympathetic autonomic functions, and EEG changes. ⋯ Analyses of EEG data indicated that acupuncture manipulation non-specifically increased power of all spectral bands except the gamma band. Furthermore, changes in HF (index of parasympathetic activity) and total power (overall activity of the autonomic nervous system) of HRV were positively correlated with changes in theta, alpha, and gamma power, while changes in LF of SBPV and LF/HF of HRV were negatively correlated with changes in power of all spectral bands. These results are consistent with the suggestion that autonomic changes induced by manipulation inducing specific acupuncture sensations might be mediated through the central nervous system, especially through the forebrain as shown in EEG changes, and are beneficial to relieve chronic pain by inhibiting sympathetic nervous activity.
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A cross-sectional study was carried out to clarify the physiological features of spontaneous awakening from nocturnal sleep (i.e., whether a child can spontaneously wake up on weekday mornings). The study population comprised 116 children at ages 5 and 6 years. Heart rate variability reflecting cardiac sympathetic and parasympathetic activities was measured. ⋯ Similarly, the parasympathetic activity was significantly lower in the children without spontaneous awakening, even in using analysis of covariance. Heart rate was significantly increased in the children without spontaneous awakening, but neither total nor nocturnal sleep durations were significant covariates in the analysis of covariance. In conclusion, the absence of spontaneous awakening from nocturnal sleep in preschool children is suggested to be characterized by short sleep duration, parasympathetic hypoactivity, and elevated heart rate.
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Nausea and vomiting following surgery may either occur as postoperative nausea and vomiting, which is a condition that is mainly related to anesthesia, or as secondary to postoperative ileus, which denotes inhibition of gastrointestinal motility following surgery. Postoperative ileus is a multifactorial event with several contributing mechanisms. ⋯ This review describes different aspects of the pathophysiology of postoperative ileus and postoperative nausea and vomiting, their relevance to postoperative care, and the standardized approach to manage postoperative nausea and vomiting that was established by Apfel and coworkers. Despite the recent advances in the understanding and treatment of conditions that trigger nausea and vomiting in the postoperative period, these symptoms remain a significant problem that affects patients' recovery, comfort, and treatment cost.
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The past 20 years have seen notable advances in our understanding of the physiology and pharmacology of the emetic reflex leading to the identification of the anti-emetic effects of 5-hydroxytryptamine(3) (5-HT(3)) and neurokinin(1) receptor (NK(1)) antagonists. The introduction of 5-HT(3) and NK(1) receptor antagonists into the clinic has had a major impact in alleviating the nausea and vomiting associated with the treatment of cancer and the sequelae to anaesthesia and surgery (post-operative nausea and vomiting, PONV). Despite these advances there are major gaps in our understanding. ⋯ Additional gaps in our knowledge are highlighted to provide a framework within which directions for research can be proposed. Particular attention is drawn to: lacunae in knowledge of some currently used anti-emetics such as the source of dopamine required to initiate emesis; the theoretical assumptions and mechanisms underlying the concept of a "universal anti-emetic"; the variety of receptors at which agonists act to have anti-emetic effects (GABA (B), CB(1), 5-HT(1A), ghrelin, opioid); issues of translation from animals to humans and the relationship between the pathways involved in emesis and certain gastrointestinal disorders such as dyspepsia and gastroesophageal reflux, with the latter being of particular interest as some agents affecting reflux are also anti-emetic. Together, the unmet clinical need to adequately control nausea, possibly by new drugs acting within the brainstem, and the significant gaps in understanding key aspects of the emetic reflex, suggest an important need to focus and re-direct research into the distressing and sometimes life-threatening symptoms of nausea and vomiting.
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Spectral analysis of heart rate variability (HRV) and related measures has been shown to be a reliable noninvasive technique enabling quantitative assessment of cardiovascular autonomic regulatory responses to autonomic regulatory mechanisms; it provides a dynamic probe of sympathetic and parasympathetic tone, reflecting the interactions between the two. Over 20 studies reported abnormalities of HRV in anxiety, and patients with heart disease and anxiety are at increased risk for morbidity and mortality. Psychiatric drugs partly correct abnormalities of HRV and, recently, autonomic drugs (beta-blockers) have been studied in anxiety disorders. The authors call for further studies, especially in patients with co-existing anxiety disorders and heart disease, incorporating assessment of HRV.