A Proposed Molecular Mechanism for Physical Analgesia in Chronic Pain

Profile of dorsal root ganglion neurons: study of oxytocin expression

Although dorsal root ganglion (DRG) neurons have been so far classified according to the difference in their fibers (Aβ, Aδ, and C), this classification should be further subdivided according to gene expression patterns. We focused on oxytocin (OXT) and its related receptors, because OXT plays a local role in DRG neurons. We measured the mRNA levels of OXT, OXT receptor (OXTR), vasopressin V1a receptor (V1aR), transient receptor potential cation channel subfamily V member 1 (TRPV1), and piezo-type mechanosensitive ion channel component 2 (Piezo2) in single DRG neurons by using real-time PCR, and then performed a cluster analysis. According to the gene expression patterns, DRG neurons were classified into 4 clusters: Cluster 1 was characterized mainly by Piezo2, Cluster 2 by TRPV1, Cluster 4 by OXTR, and neurons in Cluster 3 did not express any of the target genes. The cell body diameter of OXT-expressing neurons was significantly larger in Cluster 1 than in Cluster 2. These results suggest that OXT-expressing DRG neurons with small cell bodies (Cluster 2) and large cell bodies (Cluster 1) probably correspond to C-fiber neurons and Aβ-fiber neurons, respectively. Furthermore, the OXT-expressing neurons contained not only TRPV1 but also Piezo2, suggesting that OXT may be released by mechanical stimulation regardless of nociception. Thus, mechanoreception and nociception themselves may induce the autocrine/paracrine function of OXT in the DRG, contributing to alleviation of pain.

Protocol based pain management by Ayurveda parasurgical procedures W.S.R to musculoskeletal pain and its critical appraisal - An open labeled clinical trial

BACKGROUND

Pain has globally become an attention problem which causes discomfort by affecting the body as well as the mind. The International association of pain estimated that 1 in 5 patients experiences the pain, i.e. 30% of world population. 19.3% (180-200 million) of the total population in India suffer from chronic pain and its severity appeals early approach of patients to hospitals. Ayurveda being the oldest medical science emphasized its importance and treatment of pain with both pharmacological and non-pharmacological (Parasurgical) methods.

OBJECTIVE

To evaluate the efficacy of non-pharmacological (para surgical) procedures in the management of pain.

MATERIALS AND METHOD

Total 100 patients with chronic musculoskeletal pain fulfilling the inclusion criteria were recruited by assessing the site, severity and nature of pain. A special protocol was framed by incorporating Ayurveda treatment principles by using Para surgical procedures such as Agnikarma (Therapeutic burn), Jalauka (leech therapy), Alabu (Cupping therapy) and Siravyadha (Vein puncture). The parameters like VAS and VDS pertaining to pain were assessed from baseline and at various time points. Statistical analysis was performed by using Wilcoxon match paired test to assess the results.

RESULTS

The VAS and VDS scale were used to assess the efficacy of para-surgical procedures which was found to be significant (p < 0.0001) from baseline and at various time points.

CONCLUSION

Protocol based pain management by various para surgical procedures was found effective in the management of chronic musculoskeletal pain. The ambiguity in selection of proper parasurgical procedure for pain management is justified by following the protocol.

Dorsolateral prefrontal cortex sensing analgesia

Chronic pain often has an unknown cause, and many patients with chronic pain learn to accept that their pain is incurable and pharmacologic treatments are only temporarily effective. Complementary and integrative health approaches for pain are thus in high demand. One such approach is soft touch, e.g., adhesion of pyramidal thorn patches in a pain region. The effects of patch adhesion on pain relief have been confirmed in patients with various types of pain. A recent study using near-infrared spectroscopy revealed that the dorsolateral prefrontal cortex (DLPFC), especially the left side, is likely to be inactivated in patients experiencing pain relief during patch treatment. Mindfulness meditation is another well-known complementary and integrative approach for achieving pain relief. The relation between pain relief due to mindfulness meditation and changes in brain regions, including the DLPFC, has long been examined. In the present review article, we survey the literature describing the effects of the above-mentioned complementary and integrative treatments on pain relief, and outline the important brain regions, including the DLPFC, that are involved in analgesia. We hope that the present article will provide clues to researchers who hope to advance neurosensory treatments for pain relief without medication.

Pain relief associated with decreased oxyhemoglobin level in left dorsolateral prefrontal cortex

Pain in the elbow, shoulder, knee, lower back, and various other joints is relieved by adhesion of pyramidal thorn patches. To elucidate the pain relief mechanism induced by the patches, we established a quantitative method for estimating the pain reduction and investigated the brain regions that change in association with pain relief. We first attempted to quantify the pain relief using transcutaneous electric stimulation (TCES) and a visual analog scale (VAS), and then applied near-infrared spectroscopy (NIRS) to the prefrontal cortex, including the dorsolateral prefrontal cortex (DLPFC) and the orbitofrontal cortex (OFC). We also examined the salivary oxytocin levels, which are thought to reflect oxytocin secretion levels from the posterior pituitary in the brain. Application of pyramidal thorn patches to pain regions decreased the pain degree estimated using TCES and VAS. Oxyhemoglobin levels were likely to be decreased in the left DLPFC on the basis of NIRS measurements during patch treatment, suggesting that the left DLPFC is involved in pain relief. On the other hand, the salivary oxytocin levels varied widely. A potential reason for the varying salivary oxytocin levels is its utilization in the pain region as an analgesic agent. Our results suggest that the left DLPFC will become a target brain region for pain therapy.

Dealing with Anxious Patients: An Integrative Review of the Literature on Nonpharmaceutical Interventions to Reduce Anxiety in Patients Undergoing Medical or Dental Procedures

Objectives: A previous systematic literature review (SLR) evaluated 501 experiments on reducing patient anxiety across medical and dental environments. This integrative review examines those interventions and explores possible mechanisms leading to relative success or failure within those environments, in the interest of interprofessional education and communication. Methods: Reviewers evaluated 501 experiments testing interventions for reducing patient anxiety in a variety of medical and dental health care settings. Methodology for the SLR, largely following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, is briefly reviewed. Results: A total of 501 experiments (from 408 articles) met review criteria. One hundred and forty-three Music experiments were included, and Music interventions were largely effective, except in the case of colonoscopy. Education is the only intervention that occasionally (5 times of 130 experiments) raised patient anxiety in the face of a procedure; the discussion focuses on the wisdom of assessing patient need for information. Thirty-seven Cognitive Behavioral Therapy (CBT) experiments of various types are included, with a success rate of 89%, with a particularly high rate of success (12 of 12 experiments) in dentistry. Massage has a success rate that is similar to that of CBT, but Massage has been tested in far fewer specialty areas. Relaxation has been tested in every specialty area, except mechanical ventilation, with promising results. Acupuncture and Acupressure have not been widely tested, but their effectiveness rate is 100% when it comes to reducing patient anxiety in various procedural settings. Similarly, experiments show Hypnosis to be successful in 90% of trials. In contrast, Distraction was successful in only 40% of the experiments summarized, although it was more effective in dentistry. A variety of Nature-based Interventions (Aromatherapy, Nature Sounds, and Visual Stimuli) were highly successful across a variety of settings. Discussion: Possible mechanisms are discussed, along with commentary on feasibility. Limitations include publication bias, small sample sizes, and the lack of placebo controls. Future areas of research are pointed out.

Peripheral-neuron-like properties of differentiated human dental pulp stem cells (hDPSCs)

Elucidating the mechanisms underlying human pain sensation requires the establishment of an in vitro model of pain reception comprising human cells expressing pain-sensing receptors and function properly as neurons. Human dental pulp stem cells (hDPSCs) are mesenchymal stem cells and a promising candidate for producing human neuronal cells, however, the functional properties of differentiated hDPSCs have not yet been fully characterized. In this study, we demonstrated neuronal differentiation of hDPSCs via both their expression of neuronal marker proteins and their neuronal function examined using Ca²⁺ imaging. Moreover, to confirm the ability of nociception, Ca²⁺ responses in differentiated hDPSCs were compared to those of rat dorsal root ganglion (DRG) neurons. Those cells showed similar responses to glutamate, ATP and agonists of transient receptor potential (TRP) channels. Since TRP channels are implicated in nociception, differentiated hDPSCs provide a useful in vitro model of human peripheral neuron response to stimuli interpreted as pain.

Potential therapeutic applications of AKAP disrupting peptides

The 3'-5'-cyclic adenosine monophosphate (cAMP)/PKA pathway represents a major target for pharmacological intervention in multiple disease conditions. Although the last decade saw the concept of highly compartmentalized cAMP/PKA signaling consolidating, current means for the manipulation of this pathway still do not allow to specifically intervene on discrete cAMP/PKA microdomains. Since compartmentalization is crucial for action specificity, identifying new tools that allow local modulation of cAMP/PKA responses is an urgent need. Among key players of cAMP/PKA signaling compartmentalization, a major role is played by A-kinase anchoring proteins (AKAPs) that, by definition, anchor PKA, its substrates and its regulators within multiprotein complexes in well-confined subcellular compartments. Different tools have been conceived to interfere with AKAP-based protein-protein interactions (PPIs), and these primarily include peptides and peptidomimetics that disrupt AKAP-directed multiprotein complexes. While these molecules have been extensively used to understand the molecular mechanisms behind AKAP function in pathophysiological processes, less attention has been devoted to their potential application for therapy. In this review, we will discuss how AKAP-based PPIs can be pharmacologically targeted by synthetic peptides and peptidomimetics.

Activation of the orbitofrontal cortex by both meditation and exercise: A near-infrared spectroscopy study

In some types of meditation, such as mindfulness and Zen, breathing is the focus of attention, whereas during an excessive, short-period of anaerobic exercise, the muscles become the focus of attention. Thus, during both efforts, one’s attention is focused on a certain feature of the body. Both meditation and exercise generally provide mental refreshment to humans. We hypothesized that the same brain regions are activated by both efforts in humans. To examine this hypothesis, we engaged participants in 3 tasks: meditation, exercise, and a control task. After each task, the participants underwent a 2-back test to concentrate their thoughts, while changes in their blood hemoglobin levels were simultaneously monitored using near-infrared spectroscopy (NIRS). Seventeen participants (20–24 years of age; 11 men, 6 women) were enrolled. We applied a fast-Fourier transform (FFT) analysis to the NIRS wave data and calculated the correlation coefficients of the FFT data between (1) meditation and control, (2) exercise and control, and (3) meditation and exercise, at the orbitofrontal cortex (OFC) and dorsolateral prefrontal cortex (DLPFC), brain areas that are generally involved in mental refreshment. A significant difference in the correlation coefficients between the OFC and DLPFC was detected in the meditation and exercise analysis, and signal source analysis confirmed that the NIRS waves spread from the right and left OFC edges (i.e., right and left temples) toward the center. Our results suggest that both meditation and exercise activate the OFC, which is involved in emotional reactions and motivation behavior, resulting in mental refreshment.

A novel role of oxytocin: Oxytocin-induced well-being in humans

We review the involvement of a small molecule, oxytocin, in various effects of physical stimulation of somatosensory organs, mindfulness meditation, emotion and fragrance on humans, and then propose a hypothesis that complex human states and behaviors, such as well-being, social bonding, and emotional behavior, are explained by oxytocin. We previously reported that oxytocin can induce pain relief and described the possibility how oxytocin in the dorsal horn and/or the dorsal root ganglion relieves joint and muscle pain. In the present article, we expand our research target from the physical analgesic effects of oxytocin to its psychologic effects to upregulate well-being and downregulate stress and anxiety. For this purpose, we propose a “hypothalamic-pituitary-adrenal (HPA) axis-oxytocin model” to explain why mindfulness meditation, placebo, and fragrance can reduce stress and anxiety, resulting in contentment. This new proposed model of HPA axis-oxytocin in the brain also provides a target to address other questions regarding emotional behaviors, learning and memory, and excess food intake leading to obesity, aimed at promoting a healthy life.

Adhesive pyramidal thorn patches provide pain relief to athletes

Pain in athletes is ideally treated without systemic medicine. Therefore, complementary and alternative medicine, including patch treatments, is often used. The physiologic mechanisms of pain relief produced by patch treatment, however, are not well elucidated. In the present study, we introduce a pyramidal thorn (PT) patch that we developed, demonstrate the effects of this PT patch for the treatment of various types of pain in 300 subjects, and suggest a physiologic mechanism for the pain relief effects. One treatment with the PT patch effectively relieved pain in almost half the subjects evaluated. Except for pain generated deeply under the skin, such as low-back pain, pain was eliminated within four treatments with the PT patch in almost all of the subjects. Interestingly, the pain-sensing region moved along the nerve fibers after each trial. Further, patches without PT also provided some pain relief. We considered that this effect was due to hair deflection on the skin; that is, adhesion of the PT patch activates Merkel cells directly as well as Merkel cell-neurite complexes around the hair follicles by deflecting the hair follicles, whereas adhesion of a patch without PT only activates the Merkel cell-neurite complexes. In any case, patch adhesion stimulates Aβ fibers to alleviate pain. Finally, we found that the pain threshold is increased by electric stimulation, suggesting that the gentle adhesion of a PT patch would be more effective. To our knowledge, this is the first study to demonstrate physiologically the validity of an adherent patch for pain relief.