Effect of ABT-639 on Cav3.2 channel activity and its analgesic actions in mouse models of inflammatory and neuropathic pain.

Cav3.2 T-type calcium channels are important targets for pain relief in rodent models of inflammatory and neuropathic pain. Even though many T-type channel blockers have been tested in mice, only one molecule, ABT-639, has been tested in phase II clinical studies and did not produce analgesic effects over placebo. Here we examined the effects of ABT-639 on Cav3.2 channel activity in tsA-201 cells and dorsal root ganglion (DRG) neurons, in comparison with another established Cav3.2 inhibitor Z944. These experiments revealed that Z944 mediated ∼100-fold more potent inhibition of Cav3.2 currents than ABT-639, with the latter blocking channel activity by less than 15 percent when applied at a concentration of 30 µM. A slight increase in ABT-639 potency was observed at more depolarized holding potentials, suggesting that this compound may act preferentially on inactivated channels. We tested the effects of both compounds in the Complete Freund's Adjuvant (CFA) model of chronic inflammatory pain, and in partial sciatic nerve injury model of neuropathic pain in mice. In the neuropathic pain model, both Z944 and ABT-639 reversed mechanical hypersensitivity to similar degrees when delivered systemically, but remarkably, when delivered intrathecally, only Z944 was effective. In the CFA model, both compounds reversed thermal hyperalgesia upon systemic delivery, but only Z944 mediated pain relief upon intrathecal delivery, indicating that ABT-639 acts primarily at peripheral sites. ABT-639 lost its analgesic effects in CFA treated Cav3.2 null mice, indicating that these channels are essential for ABT-639-mediated pain relief despite its poor inhibition of Cav3.2 currents.

Physiotherapeutic treatment associated with the pain neuroscience education for patients with chronic non-specific low back pain-single-blind randomized pilot clinical trial.

OBJECTIVES: Pain Neuroscience Education (PNE) shows improvement in pain and functional capacity in patients with chronic low back pain (CLBP). Therefore, the study aimed to verify if the physiotherapeutic treatment associated with PNE decreases the functional disability of patients with nonspecific CLBP. METHODS: Forty patients were clinically evaluated and answered the following questionnaires: Brief pain inventory, Central Sensitization Inventory (CSI), Roland-Morris disability questionnaire, pain catastrophizing scale, Tampa scale of kinesiophobia, hospital anxiety, and depression scale, SF6D quality of life questionnaire and performed quantitative sensory tests (QSTs). Afterward, they were randomly divided into the intervention group (IG, n=20) and the control group (CG, n=20). Both performed kinesiotherapy exercises twice a week for 6 weeks. The IG received 3 individual PNE sessions and answered the pain neurophysiology questionnaire. RESULTS: IG showed significant improvement for all variables analyzed (p<0.001). The association decreased the kinesiophobia (estimated difference between CG-IG means: 7.6-95% CI: 2.3-12.9) (p=0.006). In the lumbar paravertebral region (CG and IG), there was a statistical difference in the intensity of CLBP in the QSTs (p<0.05). CONCLUSION: The association showed better results compared to only therapeutic exercises to reduce kinesiophobia and change the perception of pain intensity in the lumbar region.

Current Drug Development Overview: Targeting Voltage-Gated Calcium Channels for the Treatment of Pain.

Voltage-gated calcium channels (VGCCs) are targeted to treat pain conditions. Since the discovery of their relation to pain processing control, they are investigated to find new strategies for better pain control. This review provides an overview of naturally based and synthetic VGCC blockers, highlighting new evidence on the development of drugs focusing on the VGCC subtypes as well as mixed targets with pre-clinical and clinical analgesic effects.

Analgesia by intrathecal delta-9-tetrahydrocannabinol is dependent on Cav3.2 calcium channels.

Delta-9-tetrahydrocannabinol (Δ9-THC) is known to produce systemic analgesia that involves CB1 and CB2 cannabinoid receptors. However, there is compelling evidence that Δ9-THC can potently inhibit Cav3.2T-type calcium channels which are highly expressed in dorsal root ganglion neurons and in the dorsal horn of the spinal cord. Here, we investigated whether spinal analgesia produced by Δ9-THC involves Cav3.2 channels vis a vis cannabinoid receptors. We show that spinally delivered Δ9-THC produced dose-dependent and long-lasting mechanical anti-hyperalgesia in neuropathic mice, and showed potent analgesic effects in models of inflammatory pain induced by formalin or Complete Freund's Adjuvant (CFA) injection into the hind paw, with the latter showing no overt sex differences. The Δ9-THC mediated reversal of thermal hyperalgesia in the CFA model was abolished in Cav3.2 null mice, but was unaltered in CB1 and CB2 null animals. Hence, the analgesic effects of spinally delivered Δ9-THC are due to an action on T-type calcium channels, rather than activation of spinal cannabinoid receptors.

Regulation of N-type calcium channels by nociceptin receptors and its possible role in neurological disorders.

Activation of nociceptin opioid peptide receptors (NOP, a.k.a. opioid-like receptor-1, ORL-1) by the ligand nociceptin/orphanin FQ, leads to G protein-dependent regulation of Cav2.2 (N-type) voltage-gated calcium channels (VGCCs). This typically causes a reduction in calcium currents, triggering changes in presynaptic calcium levels and thus neurotransmission. Because of the widespread expression patterns of NOP and VGCCs across multiple brain regions, the dorsal horn of the spinal cord, and the dorsal root ganglia, this results in the alteration of numerous neurophysiological features. Here we review the regulation of N-type calcium channels by the NOP-nociceptin system in the context of neurological conditions such as anxiety, addiction, and pain.

Benefits of electroacupuncture and a swimming association when compared with isolated protocols in an osteoarthritis model.

Background and aim: Osteoarthritis (OA) is characterized by pain and inflammation. Electroacupuncture (EA) and swimming (SW) are non-pharmacological interventions recommended for treating OA. The study evaluated the benefits of electroacupuncture (EA) and swimming (SW) association when compared with isolated protocols in an OA rodent model. Experimental. Procedures: An ankle monoarthritis model was induced in rats by applying Complete Freund's Adjuvant (CFA). After seven days of induced OA, the groups were submitted to EA (ST36 and the GB 30 Acupoint), SW, or the EA + SW protocol. The nociceptive behavior was measured by the Von Frey test, the Cold Stimulation test, and the Paw Flick Immersion test. Inflammatory activity was evaluated by measuring TNF levels, myeloperoxidase, NAGase, immunological parameters and the histology from the subcutaneous tissue. Results: Compared to CFA group, EA decreased the nociceptive scores in the cold stimulation test (p < 0.05), and it also increased the latency time in thermal cold (p < 0.01) and heat hyperalgesia (p < 0.001). Also, EA reduced NAGase (p < 0.01). SW reduced the edema (p < 0.05) and did not increase the inflammatory infiltrates or congestion, neither in the histological measurements nor by analyzing the levels of TNF. The association of EA + SW decreased the neutrophils and the monocytes, MPO (p < 0.05), and the glutamate levels in the cerebrospinal fluid (CSF, p < 0.001). Conclusion: There were statistical differences between combination therapy and monotherapy as seen by the inflammatory parameters, which could be associate to the delay of the chronification osteoarthritis retardation. However, EA + SW did not show benefits when compared to isolated protocols in nociceptive behavior.

Curcumin for attention-deficit-hyperactivity disorder: a systematic review and preliminary behavioral investigation.

Curcumin has protective actions in neuropsychiatric disorders, acting as a neuroprotective agent. As a first approach, the study aimed at a systematic review of the potential effects of curcumin on cognitive performance for attention-deficit-hyperactivity disorder (ADHD). This research was carried out in the databases of PubMed, Embase, SciELO, the Cochrane Central Register of Controlled Trials (CENTRAL), the Web of Science, and the Grey literature. Upon discovering the scarcity of relevant studies, and knowing that curcumin might have an ADHD hyperactive and anxious behavior, the study proposed to evaluate the effects of curcumin in an ADHD phenotype of spontaneously hypertensive Wistar rats (SHR). No studies were found that related to curcumin and ADHD. Fifteen SHRs were then divided into separate groups that received water (1 mg/kg/day), curcumin (50 mg/kg/day), or methylphenidate (1 mg/kg/day) for 42 days. Behavioral tests to assess activity (Open Field Test), anxiety and impulsivity (Elevated Plus-Maze, and Social Interaction), and memory (Y-Maze, and the Object Recognition Test) were all performed. The animals that were treated with curcumin showed less anxious and hyperactive behavior, as seen in the Open Field Test and the Social Interaction Test. Anxious behavior was measured by the EPM and was not modulated by any treatment. The results of the Y-Maze Test demonstrated that curcumin improved spatial memory. In the Object Recognition Test, neither the short nor the long-term memory was improved. The treatments that were used in this study beneficially modulated the anxious and hyperactive behavior of the SHR.

Evaluation of the efficacy and toxicity of oral and topical pumpkin oil on the hair growth of mice.

This study aimed to evaluate the efficacy and safety of a topical and oral administration of pumpkin seed oil (PSO) on the hair growth of BALB/c male mice. The animals had their dorsal area shaved (2 ×2 cm) and they were divided into 6 experimental groups. They received orally saline (OS), finasteride (F), or PSO (OP) for 14 days; or topically saline (TS), minoxidil (M), or PSO (TP) for 7 days. The euthanasia of all of the mice occurred on the 22nd day, and the histological slides from the skin area were analyzed. Lipoperoxidation in the liver was assessed through the TBARS method and was also evaluated by the antioxidant enzymes (SOD and CAT). The comet assay and the micronucleus tests were performed for genotoxic/mutagenic safety analyses. A significant increase in the number of hair follicles in the TP group was seen (8.8 ± 0.8) but it was disorganized, with loose dermal collagen. Finasteride presented a significant increase in the levels of the TBARS, SOD, and CAT in the liver, and M increased the DNA damage in the blood and the liver tissues. PSO did not induce any significant changes. In addition, PSO did not induce genotoxic or mutagenic effects. In conclusion, the oral PSO for 14 days acted in the proliferation of the hair follicles, without toxicity signals in the liver. DATA AVAILABILITY: The authors confirm that all of the relevant data is included in the article and/or in the supplementary information file.

Anti-obesity, slimming, biochemical and genotoxic effects of Cordia ecalyculata in diet-induced obese rats.

BACKGROUND: Overweight and obesity are associated with deaths and diseases worldwide. Cordia ecalyculata is a plant marketed as a slimmer. METHODS: The study evaluated the anti-obesity effects of the dry extract from C. ecalyculata in rats fed with a standard diet (STD) or cafeteria diet (CD) receiving the dry extract from C. ecalyculata at 500, 1000, and 2000 mg/kg for 40 days. Furthermore, it evaluated the slimming effect on diet-induced obese rats by the treatment with the same doses for 30 days. The bodyweight of the rats, as well as the intake of food, was measured. Blood samples were collected to determine the liver function (albumin, alanine transaminase (ALT), alkaline phosphatase (ALP), glucose), renal function (urea and creatinine), and lipid profile (cholesterol, triglycerides). RESULTS: The genotoxic effect in peripheral blood was assessed through the comet assay. A lower C. ecalyculata dose significantly prevented the weight gain in rats fed with STD and CD and decreased body weight and intake food of obese rats. The biochemical parameters were not altered, except to increase the serum albumin. Only the higher dose induced DNA damage when evaluated in rats fed with CD in the slimming evaluation model used. CONCLUSIONS: These results reinforce the extract as an anti-obesity and slimming supplement.

Targeting N-type calcium channels in young-onset of some neurological diseases.

Calcium (Ca 2+) is an important second messenger in charge of many critical processes in the central nervous system (CNS), including membrane excitability, neurotransmission, learning, memory, cell proliferation, and apoptosis. In this way, the voltage-gated calcium channels (VGCCs) act as a key supply for Ca2+ entry into the cytoplasm and organelles. Importantly, the dysregulation of these channels has been reported in many neurological diseases of young-onset, with associated genetic factors, such as migraine, multiple sclerosis, and Huntington's disease. Notably, the literature has pointed to the role of N-type Ca2+ channels (NTCCs) in controlling a variety of processes, including pain, inflammation, and excitotoxicity. Moreover, several Ca2+ channel blockers that are used for therapeutic purposes have been shown to act on the N-type channels. Therefore, this review provides an overview of the NTCCs in neurological disorders focusing mainly on Huntington's disease, multiple sclerosis, and migraine. It will discuss possible strategies to generate novel therapeutic strategies.

Evaluation of lipolysis and toxicological parameters of low-level laser therapy at different wavelengths and doses in the abdominal subcutaneous tissue.

Investigate the effects of low-level lasers therapy (LLLT) aiming abdominal lipolysis. Female Wistar rats received applications of LLLT directly in the abdominal skin twice a week (5 weeks). Except the control group (n = 5), animals received treatments with red wavelength 660 nm being (I) R3.3 group (n = 5): 3.3 J/cm2, and (II) R5 group (n = 5): 5 J/cm2, or infrared wavelength 808 nm being (III) IR3.3 group (n = 5): 3.3 J/cm2, and (IV) IR5 group (n = 5): 5 J/cm2. Abdominal subcutaneous and liver tissues were evaluated histologically. Levels of thiobarbituric acid reactive substances (TBARS) and catalase (CAT) activity were analyzed in liver tissue. In the peripheral blood aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides, and total cholesterol were investigated. Micronucleus assay was performed in the bone marrow. Except for the IR3.3 group, all treated groups reduced the body weight (p < 0.001). The R5 group reduced the abdominal subcutaneous tissue weight and thickness (p < 0.05), even though all treated groups reduced the number of adipocytes and its size (p < 0.001). No histological changes in the liver. There were no alterations in the triglycerides and LDL levels. The IR5 group increased the total cholesterol levels and decreased the HDL, ALT (both p < 0.05), and AST levels (p < 0.001). The group IR3.3 showed higher levels of ALP (p < 0.01). The R3.3 group increased the TBARS and CAT activity (p < 0.05). No mutagenic effects were found. The red laser treatment at 5 J/cm2 led to lipolysis and did not alter the liver's parameters.

Neuroprotective effects of the CTK 01512-2 toxin against neurotoxicity induced by 3-nitropropionic acid in rats.

The mitochondrial inhibitor 3-nitropropionic acid (3-NP) induces excitotoxicity. The authors hypothesized that CTK 01512-2, a recombinant peptide calcium channel N-type blocker, and the TRPA1 antagonist, could show neuroprotective effects. The male Wistar rats received 3-NP [25 mg/kg (i.p.) for 7 days], and a treatment of CTK 01512-2 was delivered intrathecally (i.t.), thrice a week. The neuroprotective effects were evaluated by [18F]FDG MicroPET analysis. The CTK 01512-2 toxin was able to reestablish similar glucose uptakes on the control animals. To detect the neurobehavioral effects from 3-NP, three protocols (6.25, 12.5, 18.75 mg/kg of 3-NP (i.p.), for 3, 4, and 6 days, respectively) were evaluated by performance tests (open field test, walk footprint, elevated plus-maze, Y-maze, and the object recognition test). Important disabilities in the gait of the rats were seen, as well as memory deficits, and anxious behavior in the animals that were treated with all 3-NP protocols. The dose of 18.75 mg/kg (for 3 days) showed the most pronounced behavioral effects and lethality, while the rats treated with 12.5 mg/kg (for 4 days) showed behavioral effects similar to the 6.25 mg/kg dose (for 6 days). The third protocol was then repeated and the rats were treated with the CTK 01512-2 toxin to be evaluated behaviorally again. The recombinant peptide prevented all of the gait-evaluated parameters that were induced by 3-NP at a 6.25 mg/kg dose, which displayed an improvement in the exploratory activities. Overall, these results have reinforced the positive effects of CTK 01512-2 against the behavioral changes that were induced by the mitochondrial inhibitor 3-NP.

The effects of Brazilian chitosan-based biomaterials on wound healing in rats.

The use of natural supplies is a resource to mimic an original extracellular matrix that allows for migration, proliferation, and cellular organization. Chitosan from Brazilian Atlantic Ocean had low protein, minerals percentage and excellent antibacterial activity. The aim of this study was to evaluate and to compare the effectiveness of different types of acids as solvents with Brazilian chitosan-membrane in the healing process of skin lesions. Experimental full-thickness 2 × 2 cm wounds were created on the dorsum skin of Wistar rats. The applied different treatments were saline, collagenase®, microcrystalline chitosan salt membrane (MCSM), microcrystalline chitosan acetic acid membrane (MCAAM), and microcrystalline chitosan hydrochloric acid membrane (MCHAM). The wound repairs were measured morphologically and histologically on days 0, 3, 7, 10, and 14. The exudate formation and the final wound contractions were similar in all of the groups. There were mild exudations in the groups with chitosan-membranes, despite the formation of crust under the membrane. This configured a serum hematic aspect, but there was no impact on the healing process. The MCHAM group had more favorable aspects that histologically showed the healing phases. A significant migration of neutrophils and macrophages seen by myeloperoxidade and Beta-N-Acetylglucosaminidase activities was evident in the chitosan groups, MCHAM and MCSM, respectively. Furthermore, the MCHAM group created its histological arrangement in a dense and more consistent manner.

Phoneutria nigriventer Tx3-3 peptide toxin reduces fibromyalgia symptoms in mice.

Fibromyalgia is characterized by the amplification of central nervous system pain with concomitant fatigue, sleep, mood disorders, depression, and anxiety. It needs extensive pharmacological therapy. In the present study, Swiss mice were treated with reserpine (0.25 mg/kg, s.c.) over three consecutive days, in order to reproduce the pathogenic process of fibromyalgia. On day 4, the administrations of the Tx3-3 toxin produced significant antinociception in the mechanical allodynia (87.16% ±12.7%) and thermal hyperalgesia (49.46% ± 10.6%) tests when compared with the PBS group. The effects produced by the classical analgesics (duloxetine 30 mg/kg, pramipexole 1 mg/kg, and pregabalin 30 mg/kg, p.o., respectively) in both of the tests also demonstrated antinociception. The administrations were able to increase the levels of the biogenic amines (5-HTP and DE) in the brain. The treatments with pramipexole and pregabalin, but not duloxetine, decreased the immobility time in the FM-induced animals that were submitted to the forced swimming test; however, the Tx3-3 toxin (87.45% ± 4.3%) showed better results. Taken together, the data has provided novel evidence of the ability of the Tx3-3 toxin to reduce painful and depressive symptoms, indicating that it may have significant potential in the treatment of FM.

Adaptogenic effects of curcumin on depression induced by moderate and unpredictable chronic stress in mice.

Curcumin has been investigated for the prevention and treatment of diseases due to its anti-oxidant, anti-inflammatory, immunomodulatory, and neuroprotective actions. This current study evaluated the adaptogenic effects of a subchronic oral administration of curcumin to Swiss mice that were submitted to a chronic unpredictable mild stress (CUMS) model of depression. Four groups of mice (vehicle control, CO; curcumin control, COC; CUMS + vehicle, CUMS; CUMS + curcumin, CUMSC) were evaluated for the biochemical parameters. The CUMS model caused depressive-like and anxiety-like behavior in the animals when they were viewed in the Forced Swimming Test and in the Elevated Plus Maze Test. The treatments with curcumin prevented the depressive-like behavior in the Forced Swimming Test and they had anxiolytic effects on the non-stressed animals. This was confirmed by the Elevated Plus Maze Test. Curcumin showed antioxidant effects (IC50 of 38.86 ± 1.78 µg/mL) in the in vitro DPPH (2,2-diphenyl-1-picryl-hydrozole) test. The compound also showed antioxidant effects in vivo, increasing the catalase (CAT) levels in the brains of the stressed animals. The biochemical analyses did not reveal potential renal and hepatic damage. Together, these results have demonstrated the antidepressant and antioxidant effects of curcumin, highlighting in this mice model, the compound's novel adaptogenic potential.

Recombinant peptide derived from the venom the Phoneutria nigriventer spider relieves nociception by nerve deafferentation.

The avulsion of nerve roots of the brachial plexus that is commonly seen in motorcycle accidents is a type of neuropathy due to deafferentation. This type of pain is clinically challenging since therapeutical protocols fail or have severe side effects. Thus, it is proposed to evaluate the antinociceptive activity of the recombinant CTK 01512-2 peptide that is derived from the venom of the Phoneutria nigriventer spider, as a future new therapeutical option. The neuropathic pain was surgically induced by avulsion of the upper brachial plexus trunk in groups of male Wistar rats and after 17 days, they were treated intrathecally with morphine, ziconotide, and CTK 01512-2. Behavioral tests were performed to evaluate mechanical and thermal hyperalgesia, cold allodynia, the functional activity of the front paw, and exploratory locomotion after the treatments. The peripheral blood samples were collected 6 h after the treatments and a comet assay was performed. The spinal cord was removed for the lipoperoxidation dosing of the membranes. The cerebrospinal fluid was analyzed for the dosage of glutamate. The recombinant peptide showed an antinociceptive effect when compared to the other drugs, without affecting the locomotor activity of the animals. Mechanical and thermal hyperalgesia, as well as cold allodynia, were reduced in the first hours of treatment. The levels of glutamate and the damage by membrane lipoperoxidation were shown to be improved, and genotoxicity was not demonstrated. In a scenario of therapeutical failures in the treatment of this type of pain, CTK 01512-2 was shown as a new effective alternative protocol. However, further testing is required to determine pharmacokinetics.