RESUMO
Multiple sclerosis (MS) is a Central Nervous System inflammatory demyelinating disease that has as primary symptoms losses of sensory and motor functions, including chronic pain. To date, however, few studies have investigated the mechanisms of chronic pain in animal models of MS since locomotor impairments render difficult its evaluation. It was previously demonstrated that in the MOG35-55-induced EAE, an animal model of MS, the hypernociception appears before the onset of motor disability, allowing for the study of these two phenomena separately. Here, we evaluated the effect of crotoxin (CTX), a neurotoxin isolated from the Crotalus durissus terrificus snake venom that displays, at non-toxic dose, antinociceptive, anti-inflammatory and immunomodulatory effects, in the pain and in symptoms progression of EAE. The pain threshold of female C57BL/6 mice decreased at the 4th day after immunization, while the first sign of disease appeared around the 11st-12nd days, coinciding with the onset of motor abnormalities. CTX (40 µg/kg, s.c.) administered in a single dose on the 5th day after immunization, induced a long-lasting analgesic effect (5 days), without interfering with the clinical signs of the disease. On the other hand, when crotoxin was administered for 5 consecutive days, from 5th-9th day after immunization, it induced analgesia and also reduced EAE progression. The antinociceptive effect of crotoxin was blocked by Boc-2 (0.5 mg/kg, i.p.), a selective antagonist of formyl peptide receptors, by NDGA (30 µg/kg, i.p.), a lipoxygenase inhibitor and by atropine sulfate (10 mg/kg, i.p.), an antagonist of muscarinic receptors, administered 30 min before CTX. CTX was also effective in decreasing EAE clinical signs even when administered after its onset. Regarding the interactions between neurons and immunocompetent cells, CTX, in vitro, was able to reduce T cell proliferation, decreasing Th1 and Th17 and increasing Treg cell differentiation. Furthermore, in EAE model, the treatment with 5 consecutive doses of CTX inhibited IFN-γ-producing T cells, GM-CSF-producing T cells, reduced the frequency of activated microglia/macrophages within the CNS and decreased the number of migrating cell to spinal cord and cerebellum at the peak of the disease. These results suggest that CTX is a potential treatment not only for pain alteration but also for clinical progression induced by the disease as well as an useful tool for the development of new therapeutic approaches for the multiple sclerosis control.
Assuntos
Crotoxina , Encefalomielite Autoimune Experimental , Esclerose Múltipla , Dor , Animais , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Crotoxina/farmacologia , Crotoxina/uso terapêutico , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/tratamento farmacológico , Feminino , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Esclerose Múltipla/complicações , Esclerose Múltipla/tratamento farmacológico , Dor/tratamento farmacológico , Dor/etiologiaRESUMO
Freshwater stingray accidents cause an immediate, intense, and unrelieved pain which is followed by edema, erythema and necrosis formation. Treatment for stingray envenomation is based on administration of analgesic, antipyretic and anti-inflammatory drugs. Concerning pain control, it is prescribed to immerse punctured limb on hot water to alleviate pain. There are no studies demonstrating specific targets on which stingray venom acts to promote pain. Therefore, the aim of this work was to investigate some mechanisms of Potamotrygon motoro venom (PmV) that contribute to nociception induction. Evaluating spontaneous pain behavior in mice injected i.pl. with PmV, it was seen that PmV induced both neurogenic and inflammatory pain. PmV also induced hyperalgesia in both mice and rats, evaluated through electronic von Frey and rat paw pressure test, respectively. Partial inhibition of hyperalgesia was observed in mice treated with cromolyn or promethazine, which indicated that mast cell and histamine via H1 receptor participate in the inflammatory pain. To search for some targets involved in PmVinduced hyperalgesia, the participation of TRPV1, calcium channels, neurokinins, CGRP, and norepinephrine, was evaluated in rats. It was seen that PmV-induced hyperalgesia occurs with the participation of neurokinins, mainly via NK1 receptor, CGRP, and calcium influx, through both P/Q and L-type voltage-dependent calcium channels, besides TRPV1 activation. The data presented herein indicate that PmV causes hyperalgesia in rodents which is dependent on the participation of several neuroinflammatory mediators.
Assuntos
Venenos de Peixe/química , Inflamação/induzido quimicamente , Medição da Dor , Dor/induzido quimicamente , Animais , Comportamento Animal , Peptídeo Relacionado com Gene de Calcitonina , Histamina/metabolismo , Hiperalgesia/induzido quimicamente , Masculino , Mastócitos , Camundongos , Ratos , Ratos Wistar , Receptores Histamínicos H1 , Rajidae , TaquicininasRESUMO
Animal toxins present high selectivity and specificity for their molecular targets, and have long been considered as prototypes for developing novel drugs, with some successful cases. In this regard, the variety of molecules found in animal venoms, which can be capable of affecting vital physiological systems, have providing the development of studies focusing on turning those molecules (toxins) into therapeutics to treat several diseases, such as chronic pain, hypertension, thrombosis, cancer, and so on. However, some important issues have been responsible for disrupting the toxin-based drug discovery projects. In this review, we have briefly highlighted the development of drugs based on animal toxins, discussing some successful cases as well as the main causes of failure, pointing out the recent strategies applied to overcome the difficulties related to the translational process in this kind of development scenario.
Assuntos
Descoberta de Drogas , Peptídeos , Toxinas Biológicas , Peçonhas , Animais , Dor Crônica/tratamento farmacológico , Humanos , Hipertensão/tratamento farmacológico , Terapia de Alvo Molecular , Neoplasias/tratamento farmacológico , Peptídeos/efeitos adversos , Peptídeos/química , Peptídeos/farmacologia , Peptídeos/uso terapêutico , Trombose/tratamento farmacológico , Toxinas Biológicas/química , Toxinas Biológicas/farmacologia , Peçonhas/química , Peçonhas/farmacologiaRESUMO
BACKGROUND AND PURPOSE: Crotalphine is an antinociceptive peptide that, despite its opioid-like activity, does not induce some of the characteristic side effects of opioids, and its amino acid sequence has no homology to any known opioid peptide. Here, we evaluated the involvement of the peripheral cannabinoid system in the crotalphine effect and its interaction with the opioid system. EXPERIMENTAL APPROACH: Hyperalgesia was evaluated using the rat paw pressure test. Involvement of the cannabinoid system was determined using a selective cannabinoid receptor antagonist. Cannabinoid and opioid receptor activation were evaluated in paw slices by immunofluorescence assays using conformation state-sensitive antibodies. The release of endogenous opioid peptides from skin tissue was measured using a commercial enzyme immunoassay (EIA). KEY RESULTS: Both p.o. (0.008-1.0 µg·kg(-1) ) and intraplantar (0.0006 µg per paw) administration of crotalphine induced antinociception in PGE2 -induced hyperalgesia. Antinociception by p.o. crotalphine (1 µg·kg(-1) ) was blocked by AM630 (50 µg per paw), a CB2 receptor antagonist, and by antiserum anti-dynorphin A (1 µg per paw). Immunoassay studies confirmed that crotalphine increased the activation of both κ-opioid (51.7%) and CB2 (28.5%) receptors in paw tissue. The local release of dynorphin A from paw skin was confirmed by in vitroâ EIA and blocked by AM630. CONCLUSIONS AND IMPLICATIONS: Crotalphine-induced antinociception involves peripheral CB2 cannabinoid receptors and local release of dynorphin A, which is dependent on CB2 receptor activation. These results enhance our understanding of the mechanisms involved in the peripheral effect of crotalphine, as well as the interaction between the opioid and cannabinoid systems.
Assuntos
Analgésicos/farmacologia , Hiperalgesia/metabolismo , Peptídeos Opioides/metabolismo , Peptídeos/farmacologia , Receptor CB2 de Canabinoide/metabolismo , Pele/efeitos dos fármacos , Analgésicos/uso terapêutico , Animais , Antagonistas de Receptores de Canabinoides/farmacologia , Dinoprostona , Hiperalgesia/tratamento farmacológico , Indóis/farmacologia , Masculino , Peptídeos/uso terapêutico , Ratos , Ratos Wistar , Receptor CB2 de Canabinoide/antagonistas & inibidores , Pele/metabolismoRESUMO
OBJECTIVE: The aim of this study was to evaluate the analgesic effect of the low level laser therapy (LLLT) with a He-Ne laser on acute inflammatory pain, verifying the contribution of the peripheral opioid receptors and the action of LLLT on the hyperalgesia produced by the release of hyperalgesic mediators of inflammation. BACKGROUND DATA: All analgesic drugs have undesired effects. Because of that, other therapies are being investigated for treatment of the inflammatory pain. Among those, LLLT seems to be very promising. MATERIAL AND METHODS: Male Wistar rats were used. Three complementary experiments were done. (1) The inflammatory reaction was induced by the injection of carrageenin into one of the hind paws. Pain threshold and volume increase of the edema were measured by a pressure gauge and plethysmography, respectively. (2) The involvement of peripheral opioid receptors on the analgesic effect of the laser was evaluated by simultaneous injection of carrageenin and naloxone into one hind paw. (3) Hyperalgesia was induced by injecting PGE2 for the study of the effect of the laser on the sensitization increase of nociceptors. A He-Ne laser (632.8 nm) of 2.5 J/cm2 was used for irradiation. RESULTS: We found that He-Ne stimulation increased the pain threshold by a factor between 68% and 95% depending on the injected drug. We also observed a 54% reduction on the volume increase of the edema when it was irradiated. CONCLUSION: He-Ne LLLT inhibits the sensitization increase of nociceptors on the inflammatory process. The analgesic effect seems to involve hyperalgesic mediators instead of peripheral opioid receptors.
Assuntos
Inflamação/complicações , Inflamação/radioterapia , Terapia com Luz de Baixa Intensidade , Dor/radioterapia , Animais , Carragenina/administração & dosagem , Dinoprostona/administração & dosagem , Edema/induzido quimicamente , Edema/radioterapia , Hiperalgesia/induzido quimicamente , Hiperalgesia/radioterapia , Injeções , Masculino , Naloxona/administração & dosagem , Antagonistas de Entorpecentes/administração & dosagem , Nociceptores/efeitos da radiação , Dor/etiologia , Limiar da Dor/efeitos da radiação , Ratos , Ratos WistarRESUMO
The ability of Lys49 and Asp49 phospholipases A(2) (PLA(2)), from Bothrops asper snake venom, to cause hyperalgesia was investigated in rats, using the paw pressure test. Intraplantar injection of both toxins (5-20 micro g/paw) caused hyperalgesia, which peaked 1h after injections. Incubation of both proteins with heparin, prior to their injection, partially reduced this response. Chemical modification of Asp49 PLA(2) with p-bromophenacyl bromide (p-BPB), which abrogates its PLA(2) activity, also abolished hyperalgesia. Intraplantar injection of a synthetic peptide corresponding to the C-terminal sequence 115-129 of Lys49 PLA(2), caused hyperalgesia of similar time course, but varying magnitude, than that induced by the native protein. In contrast, a homologous peptide derived from the Asp49 PLA(2) did not show any nociceptive effect. Hyperalgesia induced by both PLA(2)s was blocked by the histamine and serotonin receptor antagonists promethazine and methysergide, respectively, by the bradykinin B(2) receptor antagonist HOE 140 and by antibodies to tumor necrosis factor alfa (TNFalpha) and interleukin 1 (IL-1). Pretreatment with guanethidine, atenolol, prazosin and yohimbine, inhibitors of sympathomimetic amines, or with indomethacin, inhibitor of the cyclo-oxygenase pathway, reduced Lys49 PLA(2)-induced hyperalgesia without interfering with the nociceptive activity of Asp49 PLA(2). The hyperalgesic response to both myotoxins was not modified by pretreatment with celecoxib, an inhibitor of the cyclo-oxygenase type II, by zileuton, an inhibitor of the lipoxygenase pathway or by N(g)-methyl-L-arginine (LNMMA), an inhibitor of nitric oxide synthase. These results suggest that Asp49 and Lys49 PLA(2)s are important hyperalgesic components of B. asper venom, and that Lys49 and Asp49 PLA(2)s exert their algogenic actions through different molecular mechanisms.
Assuntos
Bothrops , Bradicinina/análogos & derivados , Venenos de Crotalídeos/enzimologia , Hidroxiureia/análogos & derivados , Hiperalgesia/induzido quimicamente , Fosfolipases A/química , Fosfolipases A/toxicidade , Animais , Bradicinina/farmacologia , Carragenina/farmacologia , Celecoxib , Heparina/farmacologia , Membro Posterior/efeitos dos fármacos , Membro Posterior/patologia , Antagonistas dos Receptores Histamínicos/farmacologia , Hidroxiureia/farmacologia , Masculino , Peptídeos/síntese química , Peptídeos/toxicidade , Pirazóis , Ratos , Ratos Wistar , Antagonistas da Serotonina/farmacologia , Sulfonamidas/farmacologia , Fatores de Tempo , ômega-N-Metilarginina/farmacologiaRESUMO
Neutralization of hyperalgesia induced by Bothrops jararaca and B. asper venoms was studied in rats using bothropic antivenom produced at Instituto Butantan (AVIB, 1 ml neutralizes 5 mg B. jararaca venom) and polyvalent antivenom produced at Instituto Clodomiro Picado (AVCP, 1 ml neutralizes 2.5 mg B. aspar venom). The intraplantar injection of B. jararaca and B. asper venoms caused hyperalgesia, which peaked 1 and 2 h after injection, respectively. Both venoms also induced edema with a similar time course. When neutralization assays involving the independent injection of venom and antivenom were performed, the hyperalgesia induced by B. jararaca venom was neutralized only when bothropic antivenom was administered iv 15 min before venom injection, whereas edema was neutralized when antivenom was injected 15 min or immediately before venom injection. On the other hand, polyvalent antivenom did not interfere with hyperalgesia or edema induced by B. asper venom, even when administered prior to envenomation. The lack of neutralization of hyperalgesia and edema induced by B. asper venom is not attributable to the absence of neutralizing antibodies in the antivenom, since neutralization was achieved in assays involving preincubation of venom and antivenom. Cross-neutralization of AVCP or AVIB against B. jararaca and B. asper venoms, respectively, was also evaluated. Only bothropic antivenom partially neutralized hyperalgesia induced by B. asper venom in preincubation experiments. The present data suggest that hyperalgesia and edema induced by Bothrops venoms are poorly neutralized by commercial antivenoms even when antibodies are administered immediately after envenomation.
Assuntos
Antivenenos/uso terapêutico , Bothrops , Venenos de Crotalídeos/antagonistas & inibidores , Edema/tratamento farmacológico , Hiperalgesia/tratamento farmacológico , Animais , Reações Cruzadas , Avaliação Pré-Clínica de Medicamentos , Edema/induzido quimicamente , Hiperalgesia/induzido quimicamente , Testes de Neutralização , Ratos , Ratos WistarRESUMO
Neutralization of hyperalgesia induced by Bothrops jararaca and B. asper venoms was studied in rats using bothropic antivenom produced at Instituto Butantan (AVIB, 1 ml neutralizes 5 mg B. jararaca venom) and polyvalent antivenom produced at Instituto Clodomiro Picado (AVCP, 1 ml neutralizes 2.5 mg B. aspar venom). The intraplantar injection of B. jararaca and B. asper venoms caused hyperalgesia, which peaked 1 and 2 h after injection, respectively. Both venoms also induced edema with a similar time course. When neutralization assays involving the independent injection of venom and antivenom were performed, the hyperalgesia induced by B. jararaca venom was neutralized only when bothropic antivenom was administered iv 15 min before venom injection, whereas edema was neutralized when antivenom was injected 15 min or immediately before venom injection. On the other hand, polyvalent antivenom did not interfere with hyperalgesia or edema induced by B. asper venom, even when administered prior to envenomation. The lack of neutralization of hyperalgesia and edema induced by B. asper venom is not attributable to the absence of neutralizing antibodies in the antivenom, since neutralization was achieved in assays involving preincubation of venom and antivenom. Cross-neutralization of AVCP or AVIB against B. jararaca and B. asper venoms, respectively, was also evaluated. Only bothropic antivenom partially neutralized hyperalgesia induced by B. asper venom in preincubation experiments. The present data suggest that hyperalgesia and edema induced by Bothrops venoms are poorly neutralized by commercial antivenoms even when antibodies are administered immediately after envenomation
Assuntos
Animais , Ratos , Antivenenos , Bothrops , Venenos de Crotalídeos , Edema , Hiperalgesia , Testes de Neutralização , Ratos Wistar , Reações Cruzadas , Estudo de Avaliação , Edema , HiperalgesiaRESUMO
Bradykinin is involved in hyperalgesia (pain hypersensitivity) induced by Bothrops jararaca venom-intraplantar injection of B. jararaca venom (5microg/paw) in rats caused hyperalgesia, which peaked 1h after venom injection. This phenomenon was not modified by promethazine (H(1) receptor antagonist), methysergide (5-HT receptor antagonist), guanethidine (sympathetic function inhibitor), anti-TNF-alpha or anti-interleukin-1 antibodies or by the chelating agent CaNa(2)EDTA. Venom-induced hyperalgesia was blocked by the bradykinin B(2) receptor antagonist HOE 140. On the other hand, des-Arg(9), [Leu(8)]-bradykinin, a bradykinin B(1) receptor antagonist, did not modify the hyperalgesic response. These results suggest that bradykinin, acting on B(2) receptor, is a mediator of hyperalgesia induced by B. jararaca venom.
Assuntos
Bothrops/fisiologia , Bradicinina/análogos & derivados , Bradicinina/fisiologia , Venenos de Crotalídeos/toxicidade , Hiperalgesia/induzido quimicamente , Antagonistas Adrenérgicos beta/farmacologia , Animais , Bradicinina/farmacologia , Antagonistas dos Receptores da Bradicinina , Quimioterapia Combinada , Hiperalgesia/fisiopatologia , Masculino , Ratos , Ratos WistarRESUMO
The ability of Bothrops asper snake venom to cause hyperalgesia was investigated in rats, using the paw pressure test. Intraplantar injection of the venom (5-15 microg/paw) caused a dose and time-related hyperalgesia, which peaked 2h after venom injection. Bothrops asper venom-induced hyperalgesia was blocked by the bradykinin B(2) receptor antagonist HOE 140 and attenuated by dexamethasone, an inhibitor of phospholipase A(2). Inhibition of the lipoxygenase pathway by NDGA abrogated the algogenic phenomenon. The hyperalgesic response was not modified by pretreatment with indomethacin, an inhibitor of the cyclo-oxygenase pathway, by meloxicam, an inhibitor of the type 2 cyclo-oxygenase pathway, by the PAF receptor antagonist BN52021 or by anti-TNF-alpha or anti-interleukin 1 antibodies. Intraplantar injection of the venom also caused an oedematogenic response which was not modified by any of these pharmacological treatments. These results suggest that hyperalgesia induced by Bothrops asper venom is, at least partially, mediated by bradykinin, phospholipase A(2) activity and leukotrienes. Distinct mechanisms are involved in the development of hyperalgesia and oedema induced by the venom.
Assuntos
Venenos de Crotalídeos/toxicidade , Hiperalgesia/etiologia , Animais , Bradicinina/análogos & derivados , Bradicinina/farmacologia , Citocinas/antagonistas & inibidores , Edema/etiologia , Indometacina/farmacologia , Masculino , Ratos , Ratos WistarRESUMO
The antinociceptive effect of Crotalus durissus terrificus venom was investigated in a model of inflammatory hyperalgesia induced by carrageenin. The rat paw pressure test was applied before and 3 h after the intraplantar (i.pl.) injection of carrageenin. The venom administered per os before and 1 or 2 h after carrageenin blocked hyperalgesia. When carrageenin was injected in both hind paws and naloxone into one hind paw, antinociception was abolished only in the paw injected with naloxone. D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr amide (CTOP) and nor-binaltorphimine, antagonists of micro- and kappa-opioid receptors, respectively, did not alter the effect of the venom. N,N-diallyl-Tyr-Aib-Aib-Phe-Leu (ICI 174,864), an antagonist of delta-opioid receptors, antagonised this effect. Prolonged administration of the venom did not induce tolerance to this antinociceptive effect. N(G)-methyl-L-arginine (L-NMMA) and methylene blue, inhibitors of nitric oxide synthase and soluble guanylate cyclase, respectively, injected i.pl., antagonised antinociception. These data indicate that both delta-opioid receptors and nitric oxide participate in the mediation of the peripheral antinociceptive effect of C. durissus terrificus venom.
Assuntos
Analgésicos não Narcóticos/farmacologia , Venenos de Crotalídeos/farmacologia , Óxido Nítrico/fisiologia , Receptores Opioides delta/fisiologia , Animais , Arginina/metabolismo , Carragenina , GMP Cíclico/metabolismo , Edema/induzido quimicamente , Edema/prevenção & controle , Inibidores Enzimáticos/farmacologia , Hiperalgesia/induzido quimicamente , Hiperalgesia/prevenção & controle , Masculino , Azul de Metileno/farmacologia , Atividade Motora/efeitos dos fármacos , Antagonistas de Entorpecentes/farmacologia , Óxido Nítrico Sintase/antagonistas & inibidores , Ratos , Ratos Wistar , Receptores Opioides delta/antagonistas & inibidores , Receptores Opioides delta/efeitos dos fármacos , Receptores Opioides kappa/antagonistas & inibidores , Receptores Opioides mu/antagonistas & inibidores , ômega-N-Metilarginina/farmacologiaRESUMO
The antinociceptive effect of Crotalus durissus terrificus snake venom, previously demonstrated in the hot-plate test, was investigated in mice using the tail-flick model. The venom, administered by the intraperitoneal, subcutaneous or oral route, did not modify the basal latency time to the noxious stimulus and the association of the venom with morphine did not alter the opioid analgesic effect of this drug. These data indicate that the antinociceptive effect of the venom is mainly due to a supraspinally integrated response.