Anti-Inflammatory and Antipruritic Effects of Remote Ischaemic Postconditioning in a Mouse Model of Experimental Allergic Contact Dermatitis.

Background and Objectives: Allergic contact dermatitis is a common type IV hypersensitivity reaction characterised by redness, itching, oedema and thickening of the skin. It occurs in about 7% of the population and its incidence is increasing. It has been observed that the preconditioning of tissues by exposing them to transient ischemia increases resistance to subsequent permanent ischemia, and this phenomenon is called ischemic preconditioning. It has been shown that conditioning in one organ can also protect other organs. The protective effect of remote ischemic preconditioning is thought to be based on the induction of anti-inflammatory responses. The aim of this project was to investigate the anti-inflammatory and antipruritic effects of remote ischemic postconditioning in a mouse model of experimental allergic contact dermatitis. Methods: Experimental allergic contact dermatitis was induced with 1-fluoro-2,4-dinitrobenzene. Remote ischemic postconditioning was performed at 3 and 25 h after the challenge. Ear thickness and number of scratches 24 and 48 h after challenge, as well as cytokine levels and the infiltration of mast cells, neutrophils, CD4+ and CD8+ T lymphocytes in serum and ear tissue at 48 h were measured to determine the effect of RIPsC. Results: Remote ischemic postconditioning decreased ear thickness, one of the symptoms of allergic contact dermatitis (p < 0.0001). It had no significant effect on the number of scratches. It reduced serum IL-17 levels (p < 0.01). It alleviated local inflammation by suppressing CD8+ T lymphocyte and neutrophil infiltration. Conclusions: It was concluded that remote ischemic postconditioning may alleviate the symptoms of allergic contact dermatitis by suppressing CD8+ T lymphocyte and neutrophil infiltration and reducing IL-17 secretion.

Bullous scabies, the light shed on etiopathogenesis and treatment: report of five paediatric cases.

Introduction: Bullous scabies (BS) is an infrequent and atypical presentation of scabies, with a predilection for elderly males. The mechanism of BS is not fully understood; superinfection, friction due to pruritus, autoeczemation, direct injury from mite's lytic enzymes, cross-reactivity of scabies protein with basal membrane zone antigens are considered to be possible reasons. Aim: To define clinical features of paediatric BS cases, which is an extremely rare subtype of scabies. Material and methods: This is a retrospective study of paediatric BS cases seen at two tertiary care centres. Previously described bacterial culture, antibiogram and follow-up records were investigated retrospectively. Confirmed scabies cases, according to the "International Alliance for the Control of Scabies (IACS)" with bullae were included. All cases were treated with 10% sulfur ointment for 3 consecutive days, two cycles. Households of cases were also treated simultaneously. Systemic antibiotics were added to patients with elevated acute phase reactants according to the antibiogram results. Informed consent was obtained from patients' parents. Results: Five BS cases were included. Three cases were male, two cases were female. Four cases had staphylococcus aureus, one had group-A beta haemolytic streptococcus positive bullae culture. All cases achieved a rapid complete resolution of symptoms after topical 10% sulfur ointment. Conclusions: Paediatric BS is an extremely rare entity of scabies. Bacterial superinfection plays a key role in bullae formation. 10% sulfur ointment is a highly effective treatment option for paediatric BS.

The Role of Hydrogen Sulfide in the Development of Tolerance and Dependence to Morphine in Mice.

OBJECTIVE: Hydrogen sulfide is an endogenous gaseous mediator that has been indicated to have a role in pain mechanisms. In this study, we aimed to detect brain and spinal cord hydrogen sulfide levels during different phases of tolerance and dependence to morphine and to determine the effects of inhibition of endogenous hydrogen sulfide production on the development of tolerance and dependence. METHODS: Morphine tolerance and dependence was developed by subcutaneous injection of morphine (10 mg/kg) twice daily for 12 days. Physical dependence was determined by counting the jumps for 20 min, which is a withdrawal symptom occurring after a single dose of naloxone (5 mg/kg) administered intraperitoneally (i.p.). Propargylglycine (30 mg/kg, i.p.), a cystathionine-γ-lyase inhibitor, and hydroxylamine (12.5 mg/kg, i.p.), a cystathionine-ß-synthase inhibitor, were used as hydrogen sulfide synthase inhibitors. The tail-flick and hot-plate tests were used to determine the loss of antinociceptive effects of morphine and development of tolerance. RESULTS: It was found that chronic and acute uses of both propargylglycine and hydroxylamine prevented the development of tolerance to morphine, whereas they had no effect on morphine dependence. Chronic and acute administrations of hydrogen sulfide synthase inhibitors did not exert any difference in hydrogen sulfide levels in brain and spinal cords of both morphine-tolerant and -dependent animals. CONCLUSION: It has been concluded that hydrogen sulfide synthase inhibitors may have utility in preventing morphine tolerance.

The effects of epidermal growth factor on early burn-wound progression in rats.

After burns, protecting tissues by medicines in the zone of stasis reduces the width and depth of injury. This study's goal was to reduce burned tissue damage in the zone of stasis using epidermal growth factor (EGF). Forty-eight Wistar rats were separated into three groups. In all groups, the burn procedure was applied following the comb burn model. In Group 1, no postburn treatment was administered. In Group 2, physiological saline solution (0.3 cc) was injected intradermally and in Group 3, EGF (0.3 cc) was injected intradermally into stasis zone tissues after the burn procedure. Surviving tissue rates were 24.0% in Group 1, 25.3% in Group 2, and 70.2% in Group 3. The average numbers of cells stained with Nrf2, HO-1, and the number of apoptotic cells were 230, 150, and 17.5 in Group 1, 230, 145, and 15.0 in Group 2, and 370, 230, and 0 in Group 3, respectively. Values in Group 3 were found to be statistically significantly different than those of Groups 1 and 2; there was no difference between Groups 1 and 2. This study shows that EGF protects zone of stasis tissue from burn damage.

JAK/STAT pathway modulation: Does it work in dermatology?

Janus kinase-signal transducer and activator of transcription (JAK/STAT)-is an intracellular signaling pathway, which plays a key role in downstream transmission of extracellular signals from cell membrane to the cell nucleus. This pathway is activated by cytokines, which participate in inflammation, innate and acquired immune responses, and also cell growth. Recent studies point out possible disturbances in JAK/STAT pathway in various inflammatory and autoimmune skin diseases, such as atopic dermatitis, psoriasis, alopecia areata. Several molecules that modulate-inhibit-this pathway are currently under investigation for the evaluation of their clinical use in dermatological diseases. A brief overview of the therapeutical use of JAK/STAT inhibitors in dermatology will be provided here.

Endocannabinoid and N-acylethanolamide levels in rat brain and spinal cord following systemic dipyrone and paracetamol administration.

The cannabinoid system has been suspected to play a role in the mechanisms of action of dipyrone and paracetamol. Our purpose was to measure the local endocannabinoid and N-acylethanolamide levels in the brain and spinal cord of rats following dipyrone and paracetamol administration. Nociception was assessed 1, 5, and 12 h following drug injections in Wistar rats, using tail-flick and hot-plate tests. The antinociceptive effects of dipyrone (150, 300, and 600 mg/kg, i.p.) and paracetamol (30, 100, and 300 mg/kg, i.p.) were observed. After administration of the highest doses of dipyrone and paracetamol, endocannabinoid (N-arachidonoylethanolamide (AEA), 2-arachidonoylglycerol (2-AG)) and N-acylethanolamide (palmitoylethanolamide (PEA), oleoylethanolamide (OEA)) levels were measured in the periaqueductal gray (PAG), rostral ventromedial medulla (RVM), and spinal cords of rats using tandem mass spectrometry with liquid chromatography. Increased 2-AG levels were observed in the PAG and the RVM 12 h after paracetamol injection; dipyrone exerted no action on 2-AG levels. Analgesic administrations led to a reduction in AEA levels in the RVM and spinal cord; similar decreases in PEA and OEA levels were observed in the RVM and the spinal cord. Dipyrone and paracetamol administrations appear to exert complicated effects on endocannabinoid and N-acylethanolamide levels in rats.

Effects of cannabinoid modulation on hypothalamic nesfatin-1 and insulin resistance.

Both nesfatin-1 and cannabinoid systems involved in the regulation of sleep, metabolism, and food intake. The relationship between cannabinoid system and nesfatin-1 levels remains to be elucidated. This study investigated nesfatin-1 and insulin resistance in 72-h rapid eye movement (REM) sleep-deprived mice under the effects of cannabinoid, and cannabinoid receptors CB1R and CB2R blocking. Sixty mice were exposed to 72-h sleep deprivation. Groups and drug administrations were as follows: Group 1 (control) received injection of vehicle. Group 2 received WIN 55,212,2. Group 3 received AM251 (CB1R antagonist) followed by WIN 55,212,2 injection. Group 4 received SR144528 (CB2R antagonist) followed by WIN 55,212,2 injection. Group 5 received only AM251. Group 6 received only SR144528. Blood samples were collected 1 h after drug administration and prepared for biochemical measurements. Glucose levels were measured by glucometer, whereas insulin and nesfatin-1 levels were measured by ELISA. Central nesfatin-1 was also assessed using immunohistochemistry. One-way analysis of variance together with post hoc Tukey's test was used for inter-group comparisons. Serum nesfatin-1 levels were comparable in all study groups. Brain nesfatin-1 immune-positive cell count was lower in WIN group compared to controls. The administration of CB1R or CB2R antagonist prevented reduction in nesfatin-1-positive cell count. Insulin resistance was higher in WINCB2 and CB2 groups than in control and WINCB1 groups. Cannabinoid treatment reduced nesfatin-1 immunoreactivity in the central nervous system and this effect was prevented by either CB1R or CB2R antagonist pretreatment. Insulin resistance might be related to CB2 receptor activation which was independent from central nesfatin-1 immunoreactivity.

CAG polymorphism in the androgen receptor gene in women may be associated with nodulocystic acne.

INTRODUCTION: Acne vulgaris (AV) is a multifactorial, inflammatory disease of the pilosebaceous unit. Hormones play a major role in the pathogenesis of acne. In cases of hyperandrogenism; hirsutism, acne, seborrhoea and alopecia appear in women. However, severe acne can also be seen without evidence of hyperandrogenism. In this case, hypersensitivity of the androgen receptor gene (ARG) encoded in the X chromosome, which is the only receptor for androgens, can be considered. ARG contains a polymorphic CAG triple loop encoding the polyglutamine pathway at the 5'end of exon 1. AIM: To investigate CAG repeat polymorphism in the ARG in nodulocystic acne patients in Turkish population. MATERIAL AND METHODS: This prospective clinical study was conducted between 2016 and 2017 in accordance with the tenets of the Declaration of Helsinki. DNA isolation from blood was performed using the RTA® Genomic DNA Isolation Kit. The fragment lengths obtained from the device to determine CAG repeat numbers were analysed based on -288 bp length 22 CAG repeat content. RESULTS: A total of 199 subjects; 100 patients (51 males, 49 females) and 99 controls (49 males, 50 females) were included in the study. The mean allele length in the patient group was 19.34; and 19.7 in the control group. There was a statistically significant difference between female patients and the control group, when the patients and control groups were compared by gender (p = 0.0059). CONCLUSIONS: The CAG trinucleotide repeat count in the ARG may be associated with acne, without hirsutism findings.

Contribution of spinal 5-HT5A receptors to the antinociceptive effects of systemically administered cannabinoid agonist WIN 55,212-2 and morphine.

The antinociceptive effects of cannabinoids and opioids have been known for centuries. Serotonin and its receptors are also known to play important roles in nociception. However, the contribution of spinal 5-HT5A receptors in antinociceptive effects of cannabinoids and opioids has not been studied. We conducted this study to clarify spinal mechanisms of the actions of the antinociceptive effects of cannabinoids and opioids. Hot plate and tail flick tests were used to assess the antinociceptive activity in Balb/c mice. WIN 55,212-2, a nonselective CB1 and CB2 agonist, and morphine exerted significant antinociceptive effects at 1, 3, and 10 mg/kg doses administered intraperitoneally in both hot plate and tail flick tests. The selective 5-HT5A receptor antagonist SB-699551 (10 nmol/mouse) was administered intrathecally 10 min before the agonists. SB-699551 significantly reduced the antinociceptive effect of both WIN 55,212-2 and morphine. In the rotarod test, WIN 55,212-2 disrupted the motor coordination at a dose of 10 mg/kg, while morphine did not affect this function at any dose. Our findings show that spinal 5-HT5A receptors are involved in the antinociceptive effects of WIN 55,212-2 and morphine.

Decreased choroidal thickness in vitiligo patients.

BACKGROUND: Vitiligo is a disease characterized by depigmented macules and patches that occur as a result of the loss of functional melanocytes from the affected skin through a mechanism which has not been elucidated yet. Destruction of pigment cells in vitiligo may not remain limited to the skin; the eyelashes, iris, ciliary body, choroid, retinal pigment epithelium and meninges may also be affected. This study aims to compare the choroidal thickness of patients with and without vitiligo using optical coherence tomography (OCT). METHODS: Spectral-domain optical coherence tomography (SD-OCT) (Retina Scan Advanced RS-3000 NIDEK, Japan) instrument (with λ = 840 nm, 27,000 A-scans/second and 5 µm axial resolution) was used for the imaging. Statistical analysis was performed using SPSS 21.0 software package. RESULTS: In all values except optic nevre area measurements, the choroidal thickness of all vitiligo patients was found out to be thinner compared to the control group. CONCLUSIONS: In vitiligo, the choroidal thickness may be affected by the loss of melanocytes.

High asymmetric dimethylarginine, symmetric dimethylarginine and L-arginine levels in migraine patients.

Experimental and clinical data strongly suggests that nitric oxide (NO) plays a pivotal role in migraine. This is also supported by studies of migraine induced by substances that release NO. NO is synthesized from L-arginine by endothelial NO synthase (NOS). Asymmetric dimethylarginine (ADMA) is the major endogenous competitive inhibitor of NOS. Symmetric dimethylarginine (SDMA) is an inactive stereoisomer of ADMA. It may reduce NO production by competing with arginine for cellular uptake. The aim of this study was to measure the levels of ADMA, SDMA and L-arginine in migraine patients during the interictal period. One hundred migraine patients and 100 healthy volunteers were recruited. The patients were in the interictal period and classified into two groups as having migraine with aura and migraine without aura. Their serum ADMA, SDMA and L-arginine levels were measured by high-performance liquid chromotography (HPLC) method. ADMA, SDMA and L-arginine levels were significantly higher in migraine patients compared to the control group. But there was no difference between the patients with and without aura. These results suggest that NOS inhibitors and L-arginine/NO pathway plays an important role in migraine pathopysiology.

Descending serotonergic and noradrenergic systems do not regulate the antipruritic effects of cannabinoids.

BACKGROUND: For centuries, cannabinoids have been known to be effective in pain states. Itch and pain are two sensations sharing a lot in common. OBJECTIVE: The goal of this research was to observe whether the cannabinoid agonist WIN 55,212-2 reduces serotonin-induced scratching behaviour and whether neurotoxic destruction of descending serotonergic and noradrenergic pathways mediate the antipruritic effect of WIN 55,212-2. Material and methods Scratching behaviour was induced by intradermal injection of serotonin (50 µg/50 µl/mouse) to Balb/c mice. The neurotoxins 5,7-dihydroxytryptamine (5,7-DHT, 50 µg/mouse) and 6-hydroxydopamine (6-OHDA, 20 µg/mouse) are applied intrathecally to deplete serotonin and noradrenaline in the spinal cord. WIN 55,212-2 (1, 3, 10 mg/kg, i.p.) dose-dependently attenuated serotonin-induced scratches. Neurotoxic destruction of neither the serotonergic nor the noradrenergic systems by 5,7-DHT and 6-OHDA, respectively, had any effect on the antipruritic action of WIN 55,212-2. CONCLUSION: Our findings indicate that cannabinoids dose-dependently reduce serotonin-induced scratching behaviour and neurotoxic destruction of descending inhibitory pathways does not mediate this antipruritic effect.

Attenuation of serotonin-induced itch responses by inhibition of endocannabinoid degradative enzymes, fatty acid amide hydrolase and monoacylglycerol lipase.

Itch and pain are two irritating sensations sharing a lot in common. Considering the antinociceptive effects of blockade of endocannabinoid degrading enzymes in pain states, we attempted to reduce scratching behavior by endocannabinoid modulation, i.e. by inhibiting fatty acid amide hydrolase (FAAH), monoacylglycerol lipase (MAGL), or cellular uptake of endocannabinoids. Scratching behavior was induced by intradermal injection of serotonin to Balb/c mice. URB597 (10 mg/kg, i.p.), a FAAH inhibitor, JZL184 (16 mg/kg, i.p.), a MAGL inhibitor, and AM404 (10 mg/kg, i.p.), an endocannabinoid transport inhibitor, were given to evaluate the effects of endocannabinoid modulation on scratching responses. Then, the CB1 receptor antagonist, AM251 (1 mg/kg, i.p.), and the CB2 receptor antagonist, SR144528 (1 mg/kg, i.p.), were administered to determine whether cannabinoid receptors mediate these effects. URB597 and JZL184, but not AM404, attenuated serotonin-induced scratches. The inhibitory effect of URB597 was reversed by SR144528, but cannabinoid receptor antagonists had no other effects on modulation by the inhibitors. We propose that augmenting the endocannabinoid tonus by inhibition of degradative enzymes, FAAH and MAGL, but not cellular uptake, may be a novel target for the development of antipruritic agents.

Contribution of nociceptin/orphanin FQ receptors to the anti-nociceptive and hypothermic effects of dipyrone.

BACKGROUND: Dipyrone is one of the most commonly used non-opioid analgesic and antipyretic drug. Its anti-nociceptive and hypothermic effects have long been suspected to be centrally mediated. The involvement of the most recently discovered opioid peptide, nociceptin/orphanin FQ (N/OFQ), and its receptor (NOP) in pain transmission is controversial. It appears to be pro-nociceptive when administered supra-spinally, but exerts anti-nociceptive effects when injected spinally or systemically. OBJECTIVE: Investigation of the role of the N/OFQ system in paracetamol-induced anti-nociception and hypothermia led us to determine its role in the anti-nociceptive and hypothermic effects of dipyrone. Material and Methods Hot-plate and tail-flick tests were used to assess nociception, and a rectal thermometer was used to measure rectal temperature in mice. RESULTS: Mice injected with dipyrone (150, 300, 600 mg/kg, i.p.) displayed dose-related anti-nociception and hypothermia. The NOP receptor antagonist JTC-801 (3 mg/kg, i.p.), at a dose that exerted no effect when used alone, alleviated dipyrone-induced anti-nociception but did not reverse dipyrone-induced hypothermia. CONCLUSION: We conclude that NOP receptors participate in the anti-nociceptive, but not in the hypothermic, effects of dipyrone.

Micronutrient Deficiencies and Digital Computerized Phototrichogram Analysis in Telogen Effluvium: a Retrospective Correlation Study in a Tertiary Medical Center.

INTRODUCTION: Telogen effluvium (TE) is a common form of non-scarring alopecia that may manifest as acute or chronic hair shedding. Several studies evaluated a possible relationship between various vitamin and mineral deficiencies and TE, but it is still a controversial topic. OBJECTIVES: This study aimed to investigate the status of vitamin and mineral deficiencies in patients diagnosed with TE and to evaluate their correlation with anagen hair ratios (AHR) calculated with an automated digital phototrichogram (ADCP). METHODS: Electronic records of 973 TE patients were retrospectively analyzed. Demographic, clinical data, parameters such as ferritin, vitamin B12 (Vit-B12), vitamin D (Vit-D), folic acid, zinc and hemoglobin (HGB) serum levels were evaluated. Anagen to telogen hair ratios were also assessed in forty-two patients via ADCP. RESULTS: The rates of anemia, low ferritin level, and Vit-B12, folate, Vit-D, and zinc deficiencies were 11.9% (N = 109), 44% (N = 332), 1.5% (N = 13), 2.5% (N = 14), 87% (N = 51), and 4.5% (N = 2), respectively. A positive correlation was found between HGB levels and AHR in female patients (Spearman rank, r = 0.417, P = 0.008). No statistically significant relationship was found between ferritin, Vit-B12, folate, zinc serum levels and AHR. The relationship between Vit-D and AHR could not be assessed due to the insufficient number of patients with Vit-D data. CONCLUSIONS: HGB value is the only marker that is positively correlated with the AHR of patients with TE. Ordering HGB can be used as an initial test for managing TE patients cost-effectively.

The therapeutic effects of transferring remote ischemic preconditioning serum in rats with neuropathic pain symptoms.

Background and objectives: Neuropathic pain is defined as pain caused by damage to the nerve as a result of a lesion or disease. It has been shown that ischemic preconditioning exerts a protective role in various tissue injuries; however, the effect of transplantation of remote ischemic preconditioning serum (RIPCs) on neuropathic pain symptoms has not been studied. The aim of this project is to investigate the effect of RIPCs transfusion by different routes of administration on neuropathic pain symptoms. Our secondary aim was to demonstrate the role of Schwann cells in the regeneration of sciatic nerve injury and to evaluate the change in the number of glial cells in the spinal cord dorsal horn. Methods: The sciatic nerve partial ligation method was used to induce neuropathic pain. Changes in neuropathic pain symptoms were assessed by measuring thermal hyperalgesia and mechanical allodynia. To determine the possible therapeutic site, alterations in the number of spinal cord lumbar posterior horn microglia and astrocytes were evaluated by ionized calcium-binding adapter molecule 1 (iba1) and glial fibrillary acidic protein (GFAP) immunostaining. Myelin basic protein immunohistochemistry was also used to assess Schwann cell immunoreactivity in the sciatic nerve. Results: In rats that underwent partial sciatic nerve ligation, neuropathic pain symptoms developed on average on day 12 and persisted up to day 21 (p < 0.0001). RIPCs administered intravenously for five days reduced thermal hyperalgesia more than intraperitoneal and subcutaneous administration (p < 0.05). Both central glial cells appear to play a role in the effect of RIPCs. RIPCs treatment increases Schwann cell remyelination. Conclusions: Our results showed that intravenously administered RIPCs remarkably improved the neuropathic pain symptoms, thermal hyperalgesia and mechanical allodynia. Further studies are needed to evaluate the role of RIPCs transfusion on glial cells.

Intralesional Avirulent Bacillus Calmette-Guérin Injection as a Promising Method for the Treatment of Tuberculosis Verrucosa Cutis.

Cutaneous involvement is a relatively uncommon manifestation of tuberculosis (TB), particularly outside the endemic regions. Cutaneous TB manifests itself in various clinical forms, depending on the host's immune status and mode of transmission. Nonetheless, the same treatment regimen is recommended for every subtype. Tuberculosis verrucosa cutis (TBVC) is a specific subgroup in which the affected persons are usually healthy adults who are vaccinated or exposed to mycobacteria during their occupational activities. These patients have the ability to launch a strong cellular immune reaction against mycobacteria. In this article, we present an elderly patient with a 4-year history of TBVC who was treated with intralesional injection of avirulent Bacillus Calmette-Guérin (BCG) and report our clinical observation on the inflammatory and healing process of the patient's lesion following the intralesional BCG injection.

Pharmacological and behavioral characterization of the saphenous chronic constriction injury model of neuropathic pain in rats.

The aim of the present study was to develop a new experimental pain model by adapting the chronic constriction injury (CCI) model of the sciatic nerve to the exclusively sensory saphenous nerve in rats. Animals were divided into naïve, sham, and two experimental groups, in which two or four 4-0 chromic gut ligatures were loosely ligated around the saphenous nerve. Then, behavioral signs of neuropathic pain were observed for 8 weeks. In rats with four ligatures, prominent mechanical allodynia and thermal hyperalgesia developed; these behavioral signs were not prominent in rats with two ligatures. Pharmacological analysis was made in rats with four loose ligations; morphine and WIN 55,212-2, a cannabinoid agonist, reversed all of the modalities tested, whereas gabapentin only suppressed mechanical allodynia and amitriptyline only reduced mechanical hyperalgesia. Our data establish a rat model of saphenous CCI with significant allodynia and hyperalgesia, which is sensitive to a number of analgesic compounds.

The role of endocannabinoid system and TRPV1 receptors in the antidepressant and anxiolytic effects of dipyrone in chronic unpredictable mild stress in mice.

Although dipyrone is a widely used analgesic and antipyretic, its mechanism of action is not fully clarified. Recent studies have drawn attention to its central effects and its relationship with the endocannabinoid system. The endocannabinoid system plays important roles in processes such as anxiety, depression, fear, and learning-memory. In this study, we aimed to investigate whether endocannabinoid levels change in the amygdala in chronic unpredictable mild stress model in mice and whether cannabinoid and TRPV1 receptors mediate antidepressant and anxiolytic effects of dipyrone. Mice were submitted to chronic unpredictable mild stress protocol of 6-weeks, then behavioral test were performed. In the first part of the study, dipyrone was injected at doses of 150, 300, and 600 mg/kg (i.p.) during behavioral tests. In the second part, the CB1 antagonist AM 251 (1 mg/kg, i.p.), the CB2 antagonist AM630 (1 mg/kg, i.p.), and the TRPV1 antagonist capsazepine (3 mg/kg, i.p.) were administered alone or in combination with 300 mg/kg dipyrone to observe if these receptors mediate dipyrone effects. Endocannabinoid and N-acylethanolamines levels were measured by LC-MS/MS in amygdala. Our results showed that there were no changes in AEA, 2-AG, PEA, OAE levels in the amygdala in mice exposed to chronic unpredictable mild stress model; dipyrone exerted antidepressant and anxiolytic effects at doses of 300 and 600 mg/kg; its anxiolytic effect appears to be mediated via CB1 receptors, whereas TRPV1 receptors seems to mediate its antidepressant action.

Modulatory role of the endogenous nitric oxide synthase inhibitor, asymmetric dimethylarginine (ADMA), in morphine tolerance and dependence in mice.

Elevated plasma asymmetric dimethylarginine (ADMA) levels have been implicated in many cardiovascular and metabolic disorders. In the current work, we investigated the hypothesis that peripheral ADMA is an important contributor to opioid tolerance and dependence, by determining plasma ADMA levels during the development of tolerance and dependence to morphine in mice. Tolerance to and dependence on morphine were induced by repeated injections of morphine (10 mg/kg, s.c.) twice daily to male mice, divided into groups of 3-, 6-, 9- and 10-day injection duration. The loss of antinociceptive effect of morphine in the tail flick test was used for evaluating the degree of tolerance. Physical dependence was assessed following the administration of a 5 mg/kg dose of naloxone, by counting the occurrence of withdrawal jumps and forepaw tremors for 20 min. At the end of each period, animals were anesthetized and blood samples were collected from carotid artery. The plasma levels of ADMA, symmetric dimethylarginine (SDMA), L: -homoarginine and L: -arginine in morphine-tolerant and -dependent mice were not different from duration-matched control mice. Similarly, no difference was observed in plasma ADMA and the other molecules concentrations between groups of mice with different stages of development of tolerance and dependence. Our results suggest that endogenous plasma ADMA, SDMA, L: -homoarginine and L: -arginine levels remain unchanged during the development of morphine tolerance and dependence, and are not associated with these phenomena.