• The Korean Journal of Physiology and Pharmacology
• /
• v.2 no.3
• /
• pp.307-312
• /
• 1998

This study was performed to investigate the mechanism of central analgesic effects of antidepressants. Thirty four male rats were anesthetized with pentobarbital sodium (40 mg/kg, ip). A stainless steel guide cannula and a PE tube (PE10) were implanted into the lateral ventricle and cisterna magna area. Stimulating and recording electrodes were implanted into the incisor pulp and anterior digastric muscle. Electrodes were led subcutaneously to the miniature cranial connector sealed on the top of the skull with acrylic resin. The jaw opening reflex was used in freely moving rats, and antidepressants were administered intracisternally in order to eliminate the effects of anesthetic agents on the pain assessment and evaluate the importance of the central action site of antidepressants. After 48 hours of recovery from surgery, digastric electromyogram (dEMG) of freely moving rats was recorded. Electrical shocks (200 ${\mu}sec$ duration, 0.5-2 mA intensity) were delivered at 0.5 Hz to the dental pulp every 2 minute. Intracisternal administration of $15\;{\mu}g$ imipramine suppressed dEMG elicited by noxious electrical stimulation in the tooth pulp to $76{\pm}6%$ control. Intracisternal administration of $30\;{\mu}g$ desipramine, nortriptyline, or imipramine suppressed dEMG remarkably to $48{\pm}2,\;27{\pm}8,\;or\;25{\pm}5%$ of the control, respectively. Naloxone, methysergide, and phentolamine blocked the suppression of dEMG produced by intracisternal antidepressants from $23{\pm}2\;to\;69{\pm}4%,\;from\;32{\pm}5\;to\;80{\pm}9%,\;and\;from\;24{\pm}6\;to\;77{\pm}5%$ of the control, respectively. These results indicate that antidepressants produce antinociception through central mechanisms in the orofacial area. Antinociception of intracisternal antidepressants seems to be mediated by an augmentation of descending pain inhibitory influences on nociceptive pathways.

• The Korean Journal of Physiology and Pharmacology
• /
• v.20 no.5
• /
• pp.525-531
• /
• 2016

The analgesic mechanism of opioids is known to decrease the excitability of substantia gelatinosa (SG) neurons receiving the synaptic inputs from primary nociceptive afferent fiber by increasing inwardly rectifying $K^+$ current. In this study, we examined whether a ${\mu}$-opioid agonist, [D-Ala2,N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO), affects the two-pore domain $K^+$ channel (K2P) current in rat SG neurons using a slice whole-cell patch clamp technique. Also we confirmed which subtypes of K2P channels were associated with DAMGO-induced currents, measuring the expression of K2P channel in whole spinal cord and SG region. DAMGO caused a robust hyperpolarization and outward current in the SG neurons, which developed almost instantaneously and did not show any time-dependent inactivation. Half of the SG neurons exhibited a linear I~V relationship of the DAMGO-induced current, whereas rest of the neurons displayed inward rectification. In SG neurons with a linear I~V relationship of DAMGO-induced current, the reversal potential was close to the $K^+$ equilibrium potentials. The mRNA expression of TWIK (tandem of pore domains in a weak inwardly rectifying $K^+$ channel) related acid-sensitive $K^+$ channel (TASK) 1 and 3 was found in the SG region and a low pH (6.4) significantly blocked the DAMGO-induced $K^+$ current. Taken together, the DAMGO-induced hyperpolarization at resting membrane potential and subsequent decrease in excitability of SG neurons can be carried by the two-pore domain $K^+$ channel (TASK1 and 3) in addition to inwardly rectifying $K^+$ channel.

• Korean Journal of Acupuncture
• /
• v.22 no.1
• /
• pp.133-150
• /
• 2005

Objective : The purpose of this study is to examine the tendency of experimental studies on the physiological effects of acupuncture at $ST_{36}$(Zusanli). Methods : We investigated 69 theses (10 Korean and 59 international) which were searched by the keyword 'Zusanli' through PubMed website, and that were experimented with manual acupuncture or electroacupuncture on healthy human subjects or normal animals. Results : The 69 theses were classified into iou groups based on the main topic which is related with the influence of acupuncture stimulation at $ST_{36}$(Zusanli), such as digestive system, nervous system, immune system, and cardiovascular system. The main results found in this study are : 1. Acupuncture at $ST_{36}$(Zusanli) increases gastric mobility. And such effect is related with vagal nerve and opioid pathway. 2. Acupuncture at $ST_{36}$(Zusanli) is valuably related with cerebral cortex. And it influences on the cerebrum activities. 3. Acupuncture at $ST_{36}$(Zusanli) has noticeable analgesic effect, which is related with Opioid mechanism, Gate control and SP 4. Acupuncture at $ST_{36}$(Zusanli) increases immunity Conclusion . Acupuncture at $ST_{36}$(Zusanli) has many effects on digestive system, nervous system, immune system, and cardiovascular system.

• The Korean Journal of Pain
• /
• v.32 no.3
• /
• pp.160-167
• /
• 2019

Background: Pain is a complex mechanism which involves different systems, including the opioidergic and GABAergic systems. Due to the side effects of chemical analgesic agents, attention toward natural agents have been increased. Artemisinin is an herbal compound with widespread modern and traditional therapeutic indications, which its interaction with the GABAergic system and antinoniceptive effects on neuropathic pain have shown. Therefore, this study was designed to evaluate the antinociceptive effects of artemisinin during inflammatory pain and interaction with the GABAergic and opioidergic systems by using a writhing response test. Methods: On the whole, 198 adult male albino mice were used in 4 experiments, including 9 groups (n = 6) each with three replicates, by intraperitoneal (i.p.) administration of artemisinin (2.5, 5, and 10 mg/kg), naloxone (2 mg/kg), bicuculline (2 mg/kg), saclofen (2 mg/kg), indomethacin (5 mg/kg), and ethanol (10 mL/kg). Writhing test responses were induced by i.p. injection of 10 mL/kg of 0.6% acetic acid, and the percentage of writhing inhibition was recorded. Results: Results showed significant dose dependent anti-nociceptive effects from artemisinin which, at a 10 mg/kg dose, was statistically similar to indomethacin. Neither saclofen nor naloxone had antinociceptive effects and did not antagonize antinociceptive effects of artemisinin, whereas bicuculline significantly inhibited the antinocicptive effect of artemisinin. Conclusions: It seems that antinocicptive effects of artemisinin are mediated by $GABA_A$ receptors.

• Journal of Oriental Neuropsychiatry
• /
• v.31 no.4
• /
• pp.269-278
• /
• 2020

Objectives: Yukmijihwang-won (Liuweidihuang-wan in Chinese) is a frequently used medicinal herbal formula. It is used as Yin tonic in Korea and China to recover patients from Yin deficiency. However, the scientific evidence on this drug has not revealed the beneficial effect or mechanism of its effects on the neurological disorder. We designed this study to examine the antidepressive and analgesic effects of Yukmijihwang-won (YJ-01) and the minor modification of YJ-01, YJ-06 on the reserpine-induced pain-depression dyad mice model. Methods: Reserpine (1 mg/kg) was administered subcutaneously once a day for three consecutive days to induce pain and depression-like behavior. The oral administration of YJ-01 and YJ-06 (100, 200, or 300 mg/kg) was performed once daily from three days after the reserpine injection. Results: Repeated administration of the YJs significantly reduced the immobility time in a forced swimming test and increased the moved distance and number of crossings in the open field test. In the von-Frey filament test, the oral administration of YJs remarkably suppressed the increase in paw withdrawal frequency. Conclusions: The results of this study suggest that YJ-01 and 06 may be good candidates to treat the pain-depression dyad.

• Journal of the Korean Orthopaedic Association
• /
• v.55 no.1
• /
• pp.9-28
• /
• 2020

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most commonly used drugs worldwide for chronic pain, such as arthritis, and there are many different types depending on their composition and mechanism. After long-term use, various side effects can occur, such as gastrointestinal and cardiovascular complications. With a similar analgesic effect to that of traditional non-selective NSAIDs, cyclooxygenase-2-selective NSAIDs have been highly anticipated, because they could complement gastrointestinal tolerance. On the other hand, because of concerns about cardiovascular safety in 2004 and 2005, and the license withdrawals of rofecoxib and valdecoxib, the interest in the side effects of NSAIDs is increasing. Therefore, it is important to use the necessary drugs at a minimum, considering the side effects and interactions of each drug. This study examined the side effects and characteristics of each NSAID that may occur and reviewed the recent research and guidelines related to the use of non-selective NSAIDs and cyclooxygenase-2-selective NSAIDs.

• The Korean Journal of Pain
• /
• v.35 no.4
• /
• pp.391-402
• /
• 2022

Background: The mechanism of peripheral axon transport in neuropathic pain is still unclear. Chemokine ligand 13 (CXCL13) and its receptor (C-X-C chemokine receptor type 5, CXCR5) as well as GABA transporter 1 (GAT-1) play an important role in the development of pain. The aim of this study was to explore the axonal transport of CXCL13/CXCR5 and GAT-1 with the aid of the analgesic effect of botulinum toxin type A (BTX-A) in rats. Methods: Chronic constriction injury (CCI) rat models were established. BTX-A was administered to rats through subcutaneous injection in the hind paw. The pain behaviors in CCI rats were measured by paw withdrawal threshold and paw withdrawal latencies. The levels of CXCL13/CXCR5 and GAT-1 were measured by western blots. Results: The subcutaneous injection of BTX-A relieved the mechanical allodynia and heat hyperalgesia induced by CCI surgery and reversed the overexpression of CXCL13/CXCR5 and GAT-1 in the spinal cord, dorsal root ganglia (DRG), sciatic nerve, and plantar skin in CCI rats. After 10 mmol/L colchicine blocked the axon transport of sciatic nerve, the inhibitory effect of BTX-A disappeared, and the levels of CXCL13/CXCR5 and GAT-1 in the spinal cord and DRG were reduced in CCI rats. Conclusions: BTX-A regulated the levels of CXCL13/CXCR5 and GAT-1 in the spine and DRG through axonal transport. Chemokines (such as CXCL13) may be transported from the injury site to the spine or DRG through axonal transport. Axon molecular transport may be a target to enhance pain management in neuropathic pain.

• The Korean Journal of Pain
• /
• v.37 no.3
• /
• pp.218-232
• /
• 2024

Background: Cynara scolymus has bioactive constituents and has been used for therapeutic actions. The present study was undertaken to investigate the mechanisms underlying pain-relieving effects of the hydroethanolic extract of C. scolymus (HECS). Methods: The antinociceptive activity of HECS was assessed through formalin and acetic acid-induced writhing tests at doses of 50, 100 and 200 mg/kg intraperitoneally. Additionally, naloxone (non-selective opioid receptors antagonist, 2 mg/kg), atropine (non-selective muscarinic receptors antagonist, 1 mg/kg), chlorpheniramine (histamine H₁-receptor antagonist, 20 mg/kg), cimetidine (histamine H₂-receptor antagonist, 12.5 mg/kg), flumazenil (GABA_A/BDZ receptor antagonist, 5 mg/kg) and cyproheptadine (serotonin receptor antagonist, 4 mg/kg) were used to determine the systems implicated in HECS-induced analgesia. Impact of HECS on locomotor activity was executed by open-field test. Determination of total phenolic content (TPC) and total flavonoid content (TFC) was done. Evaluation of antioxidant activity was conducted employing 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. Results: HECS (50, 100 and 200 mg/kg) significantly indicated dose dependent antinociceptive activity against pain-related behavior induced by formalin and acetic acid (P < 0.001). Pretreatment with naloxone, atropine and flumazenil significantly reversed HECS-induced analgesia. Antinociceptive effect of HECS remained unaffected by chlorpheniramine, cimetidine and cyproheptadine. Locomotor activity was not affected by HECS. TPC and TFC of HECS were 59.49 ± 5.57 mgGAE/g dry extract and 93.39 ± 17.16 mgRE/g dry extract, respectively. DPPH free radical scavenging activity (IC₅₀) of HECS was 161.32 ± 0.03 ㎍/mL. Conclusions: HECS possesses antinociceptive activity which is mediated via opioidergic, cholinergic and GABAergic pathways.

• Journal of Dental Anesthesia and Pain Medicine
• /
• v.19 no.6
• /
• pp.343-351
• /
• 2019

Background: Preterm labor and miscarriage may occur in stressful situations, such as a surgical operation or infection during pregnancy. Pharyngeal and buccal abscess and facial bone fractures are inevitable dental surgeries in pregnant patients. Remifentanil is an opioid analgesic that is commonly used for general anesthesia and sedation. Nonetheless, no study has investigated the effects of remifentanil on amniotic epithelial cells. This study evaluated the effects of remifentanil on the factors related to uterine contraction and its mechanism of action on amniotic epithelial cells. Methods: Amniotic epithelial cells were preconditioned at various concentrations of remifentanil for 1 h, followed by 24-h lipopolysaccharide (LPS) exposure. MTT assays were performed to assess the cell viability in each group. The effects of remifentanil on factors related to uterine contractions in amniotic epithelial cells were assessed using a nitric oxide (NO) assay, western blot examinations of the expression of nuclear factor-kappa B (NF-κB), cyclooxygenase 2 (COX2), and prostaglandin E2 (PGE₂), and RT-PCR examinations of the expression of the proinflammatory cytokines interleukin (IL)-1β and tumor necrosis factor-alpha (TNF-α). Results: Remifentanil did not affect viability and nitric oxide production of amniotic epithelial cells. Western blot analysis revealed that remifentanil preconditioning resulted in decreased expressions of NF-κB and PGE2 in the cells in LPS-induced inflammation, and a tendency of decreased COX2 expression. The results were statistically significant only at high concentration. RT-PCR revealed reduced expressions of IL-1β and TNF-α. Conclusions: Preconditioning with remifentanil does not affect the viability of amniotic epithelial cells but reduces the expression of factors related to uterine contractions in situations where cell inflammation is induced by LPS, which is an important inducer of preterm labor. These findings provide evidence that remifentanil may inhibit preterm labor in clinical settings.

• Journal of Acupuncture Research
• /
• v.34 no.4
• /
• pp.153-158
• /
• 2017

Background: Hominis placenta (HP) is used in Korean medicine to tonify qi and blood, and enrich yin and tonify yang. HP has been reported to have therapeutic effects. Methods: A survey of international and Korean electronic databases was conducted using the search terms "hominis placenta pharmacopuncture" and "hominis placenta extract". The search was limited to material published up to May 31, 2017. Results: A total of 83 studies were included in this systematic review: 50 were clinical studies, 25 were basic studies, and 8 were other types of study. Among clinical studies, the most frequently treated disease groups were musculoskeletal diseases and nervous system diseases. In vitro studies were conducted mainly on anti-inflammatory, analgesic, and anti-cell necrosis models. Most of the in vivo studies were performed in rheumatoid arthritis or diabetic complications models. Conclusion: HP pharmacopuncture has effects in the treatment of various diseases. Further large-scale randomized controlled trials are needed to improve the level of evidence for HP pharmacopuncture. It would be helpful if future in vitro and in vivo studies could identify the mechanism of action of HP pharmacopuncture.