Understanding zebrafish sleep and wakefulness physiology as an experimental model for biomedical research

Sleep is a globally observable fact, or period of reversible distracted rest, that can be distinguished from arousal by various behavioral criteria. Although the function of sleep is an evolutionarily conserved behavior, its mechanism is not yet clear. The zebrafish (Danio rerio) has become a valuable model for neurobehavioral studies such as studying learning, memory, anxiety, and depression. It is characterized by a sleep-like state and circadian rhythm, making it comparable to mammals. Zebrafish are a good model for behavioral studies because they share genetic similarities with humans. A number of neurotransmitters are involved in sleep and wakefulness. There is a binding between melatonin and the hypocretin system present in zebrafish. The full understanding of sleep and wakefulness physiology in zebrafish is still unclear among researchers. Therefore, to make a clear understanding of the sleep/wake cycle in zebrafish, this article covers the mechanism involved behind it, and the role of the neuromodulator system followed by the mechanism of the HPA axis.

Antihistamine promotes electroacupuncture analgesia in healthy human subjects: A pilot study

Background and aim

We have previously reported that histamine H₁ receptor antagonists facilitate electroacupuncture (EA) analgesia in experimental animals. In this pilot study, we sought to determine whether the histamine H₁ receptor antagonist dexchlorpheniramine (DCPA) facilitates EA analgesia in healthy human subjects.

Experimental procedure

Forty healthy subjects aged 20–30 years were randomly allocated to 1 of 4 groups: (1) sham EA at acupoints Zusanli (ST36) and Yanglingquan (GB34) (sham EA; n = 10); (2) EA at ST36 and GB34 (n = 10); (3) EA at ST36 and GB34 plus low-dose DCPA (2 mg, n = 10); (4) EA at ST36 and GB34 plus high-dose DCPA (4 mg, n = 10). Before and after acupuncture treatment, pain thresholds were determined by transcutaneous electrical stimuli on the glabrous skin of the left upper arm.

Results

After the acupuncture session, subjects in the EA plus high-dose DCPA group had a significantly higher pain threshold elevation compared with the other 3 study groups. The change from baseline in pain threshold in the EA plus high-dose DCPA group was significantly greater than the change in pain threshold with EA only, indicating that DCPA 4 mg facilitated EA analgesia.

Conclusion

The results suggest that combining H₁ receptor antagonist treatment with EA appears to relieve pain to a greater extent compared with EA alone. This study is registered with ClinicalTrials.gov (https://clinicaltrials.gov/), number NCT03805035 (https://clinicaltrials.gov/ct2/show/NCT03805035).

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Histamine H₁ receptor antagonist treatment appears to augment the pain-relieving effects of EA in healthy subjects.

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EA increased the pain thresholds in EA treated groups.

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Combination of EA and high-dose of DCPA further increased pain thresholds.

Manual Acupuncture at ST37 Modulates TRPV1 in Rats with Acute Visceral Hyperalgesia via Phosphatidylinositol 3-Kinase/Akt Pathway

Acupuncture can significantly ameliorate inflammatory pain in acute visceral hyperalgesia. Hyperalgesia is attenuated by inflammatory mediators that activate transient receptor potential vanilloid 1 (TRPV1), and TRPV1 is regulated by nerve growth factor (NGF)-induced phosphatidylinositol 3-kinase (PI3K)/Akt pathway. However, it is unknown whether NGF-induced PI3K/Akt pathway is associated with manual acupuncture (MA). In this study, the effect and mechanism of MA at Shangjuxu (ST37) and Quchi (LI11) were examined using an acetic acid-induced rat model with visceral hyperalgesia. We demonstrated that MA at ST37 significantly decreased abdominal withdrawal reflex (AWR) scores, proinflammatory cytokine expression (TNF-α, IL-1β, and IL-6), and TRPV1 protein and mRNA expression in rats with acute visceral hyperalgesia compared with the untreated controls, while MA at LI11 showed no effect. The effects of MA at ST37 were reversed after treatment with the PI3K agonist IGF-1 30 min before MA. In rats with visceral hyperalgesia, the upregulation of NGF, tropomyosin-receptor-kinase A (TrkA), PI3K, and phosphorylation-Akt (p-Akt) was decreased by MA at ST37, indicating that TRPV1 regulation via the NGF-induced PI3K/Akt pathway plays a vital role in the effects of MA-mediated amelioration of acute visceral hyperalgesia.

The Role of Skin Mast Cells in Acupuncture Induced Analgesia in Animals: A Preclinical Systematic Review and Meta-analysis

While mast cells (MCs) are previously well-known as a pathological indicator of pain, their role in alleviating pain is recently emerged in acupuncture research. Thus, this study systematically reviews the role of MC in acupuncture analgesia. Animal studies on MC changes associated with the acupuncture analgesia were searched in PubMed and EMBASE. The MC number, degranulation ratio and pain threshold changes were collected as outcome measures for meta-analyses. Twenty studies were included with 13 suitable for meta-analysis, most with a moderate risk of bias. A significant MC degranulation after acupuncture was indicated in the normal and was significantly higher in the pain model. In the subgroup analysis by acupuncture type, manual (MA) and electrical (EA, each P < .00001) but not sham acupuncture had significant MC degranulation. Meta-regression revealed the linear proportionality between MC degranulation and acupuncture-induced analgesia (P < .001), which was found essential in MA (P < .00001), but not in EA (P = .45). MC mediators, such as adenosine and histamine, are involved in its mechanism. Taken together, skin MC is an essential factor for acupuncture-induced analgesia, which reveals a new aspect of MC as a pain alleviator. However, its molecular mechanism requires further study. PERSPECTIVE: This systematic review synthesizes data from studies that examined the contribution of skin MC in acupuncture analgesia. Current reports suggest a new role for skin MC and its mediators in pain alleviation and explain a peripheral mechanism of acupuncture analgesia, with suggesting the need of further studies to confirm these findings.

Acupuncture for Cancer Pain - An Adjuvant Therapy for Cancer Pain Relief

As current pain management methods cannot effectively control pain among cancer patients, acupuncture has developed as an adjuvant therapy for cancer pain relief. However, the efficacy of acupuncture in treating cancer pain remains controversial. Here, we briefly introduced the development of pain management, analgesic mechanisms, and acupuncture methods. Meanwhile, a comprehensive overview of acupuncture programs was provided in terms of different cancer types, sources, and degrees. Interestingly, acupuncture can treat both tumor-induced pain and therapy-induced pain well among cancer patients. We preliminarily summarized frequently-used acupoints for different types of cancer pain and found that needle retention time was mostly 30 min, and treatment cycle was two weeks. Additionally, clinicians consistently selected Ashi acupoint or bilateral Zusanli acupoint and combined multiple acupuncture methods for different degrees of cancer pain.

Endogenous Opiates and Behavior: 2018

This paper is the forty-first consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2018 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (2), the roles of these opioid peptides and receptors in pain and analgesia in animals (3) and humans (4), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (5), opioid peptide and receptor involvement in tolerance and dependence (6), stress and social status (7), learning and memory (8), eating and drinking (9), drug abuse and alcohol (10), sexual activity and hormones, pregnancy, development and endocrinology (11), mental illness and mood (12), seizures and neurologic disorders (13), electrical-related activity and neurophysiology (14), general activity and locomotion (15), gastrointestinal, renal and hepatic functions (16), cardiovascular responses (17), respiration and thermoregulation (18), and immunological responses (19).

Effects of Herbal Medicines on Pain Management

Pain is an unpleasant sensory and emotional experience in many diseases and is often caused by intense or damaging stimuli. Pain negatively affects the quality of life and increases high health expenditures. Drugs with analgesic properties are commonly used to relieve pain, but these Western medications could be overwhelmed by side effects including tolerance and addiction. Herbal medicines may provide alternative measures for pain management. In this review paper, after introduction of Chinese medicine theory and treatment modality, emphasis is placed on the application of Chinese herbs and herbal formulations in pain management. Three of the most commonly used herbs, i.e., Corydalis yanhusuo, Ligusticum chuanxiong, and Aconitum carmichaeli, are reviewed. Subsequently, using this ancient medical remedy, Chinese herbal formulation in treating common medical conditions associated with pain, such as headache/migraine, chest pain, abdominal pain, low back pain, neuropathic pain, osteoarthritis, and cancer pain, is presented. Chinese herbal medicines could be considered as a complementary and integrative approach in the modern armamentarium in combating pain.

Research Advances on Acupuncture Analgesia

Pain is a widespread and complex symptom which causes serious emotional and social burdens to individuals and society. Most patients with pain rely heavily on over the counter (OTC) and prescription pain killers. However, there would be a number of issues that arise from the use of pain killers, in which safety and addiction are the most critical issues. For traditional Chinese medicine (TCM), pain is a result of the meridians being blocked. This could occur as a symptom of or be caused by various diseases. In this case, the key to relieve pain depends on dredging the meridian or meridians. Acupuncture has been practiced in China for over 2000 years to lessen pain. It is based on the “meridian theory”. Acupuncture is being used more widely and with a growing number of people in the treatment of pain because it is safer and has fewer side effects. Along with growing use and interest in acupuncture to treat pain, more attention has been paid to the mechanism underlying its analgesic effect, which is mainly associated with the changes of neurotransmitters. In this review, we summarize and analyze the range and mechanism of acupuncture analgesia treatment.

Transcutaneous Electrical Acupoint Stimulation for Improving Postoperative Recovery, Reducing Stress and Inflammatory Responses in Elderly Patient Undergoing Knee Surgery

Transcutaneous electrical acupoint stimulation (TEAS) is a form of acupuncture treatment that applies electrical stimulation on specific acupoint through cutaneous electrodes. This technique has been used for perioperative anesthesia management as part of after surgery recovery. However, to date, limited data are available for using the TEAS for postoperative recovery in elderly surgical patients. We conducted this prospective randomized sham-control trail to evaluate the efficacy of TEAS in a group of elderly patients receiving knee surgery under epidural anesthesia. 52 subjects were assigned to either the experimental group (Group E) or control group (Group C). The patients in Group E received TEAS at zusanli (ST36), sanyinjiao (SP6), neiguan (PC6), and quchi acupoints (LI11) 30[Formula: see text]min prior to the epidural anesthesia and postoperative day 1 and 2, while patients in Group C received sham TEAS on the same acupoints for 30[Formula: see text]min same as those of Group E. The primary endpoint was the Quality of Recovery-40 questionnaire (QR-40) and the secondary endpoints were the biomarkers level of stress and inflammatory responses and visual analogue scale (VAS). A one-way ANOVA (SNK method) was used in statistic, and [Formula: see text] is considered to be statistically significant. Our data showed that the QoR-40 was significantly lower in Group C than that in Group E at postoperative day 1 ([Formula: see text]); Similarly, Cortisol (COR), Adrenocorticotropic Hormone (ACTH), and C-reactive protein (CRP) were significantly lower in Group E than those of Group C at postoperative day 1, 3, and 7 ([Formula: see text]), while the neutrophil/lymphocyte ratio (N/L) was lower in Group E than that in Group C at postoperative day 1 and 3 ([Formula: see text]). Our results showed that perioperative TEAS administration is able to facilitate the development of postoperative recovery of elderly patients, especially at the early stage after surgery. The reported results are likely to be mediated by the reduction of surgical inflammation and perioperative stress response.

Manual acupuncture relieves bile acid-induced itch in mice: the role of microglia and TNF-α

Pruritus, or itch, is a frequent complaint amongst patients with cholestatic hepatobiliary disease and is difficult to manage, with many patients refractory to currently available antipruritic treatments. In this study, we examined whether manual acupuncture (MA) at particular acupoints represses deoxycholic acid (DCA)-induced scratching behavior and microglial activation and compared these effects with those induced by another pruritogen, 5'-guanidinonaltrindole (GNTI, a kappa opioid receptor antagonist). MA at Hegu (LI4) and Quchi (LI11) acupoints significantly attenuated DCA- and GNTI-induced scratching, whereas no such effects were observed at the bilateral Zusanli acupoints (ST36). Interestingly, GNTI-induced scratching was reduced similarly by both MA and electroacupuncture (EA) at the LI4 and LI11 acupoints. MA at non-acupoints did not affect scratching behavior. Intraperitoneal injection of minocycline (a microglial inhibitor) reduced GNTI- and DCA-induced scratching behavior. In Western blot analysis, subcutaneous DCA injection to the back of the neck increased spinal cord expression of ionized calcium-binding adapter molecule 1 (Iba1) and tumor necrosis factor-alpha (TNF-α) as compared with saline injection, while MA at LI4 and LI11 reduced these DCA-induced changes. Immunofluorescence confocal microcopy revealed that DCA-induced Iba1-positive cells with thicker processes emanated from the enlarged cell bodies, while this effect was attenuated by pretreatment with MA. It is concluded that microglia and TNF-α play important roles in the itching sensation and MA reduces DCA-induced scratching behavior by alleviating spinal microglial activation. MA may be an effective treatment for cholestatic pruritus.