concanavalin-a and Pain

Proopiomelanocortin (POMC)-derived beta-endorphin1-31 from immune cells can inhibit inflammatory pain. Here we investigated cytokine signaling pathways regulating POMC gene expression and beta-endorphin production in lymphocytes to augment such analgesic effects.. Interleukin-4 dose-dependently elevated POMC mRNA expression in naïve lymph node-derived cells in vitro, as determined by real-time PCR. This effect was neutralized by janus kinase (JAK) inhibitors. Transfection of Signal Transducer and Activator of Transcription (STAT) 1/3 but not of STAT6 decoy oligonucleotides abolished interleukin-4 induced POMC gene expression. STAT3 was phosphorylated in in vitro interleukin-4 stimulated lymphocytes and in lymph nodes draining inflamed paws in vivo. Cellular beta-endorphin increased after combined stimulation with interleukin-4 and concanavalin A. Consistently, in vivo reduction of inflammatory pain by passively transferred T cells improved significantly when donor cells were pretreated with interleukin-4 plus concanavalin A. This effect was blocked by naloxone-methiodide.. Interleukin-4 can amplify endogenous opioid peptide expression mediated by JAK-STAT1/3 activation in mitogen-activated lymphocytes. Transfer of these cells leads to inhibition of inflammatory pain via activation of peripheral opioid receptors.

Topics: Animals; Cells, Cultured; Concanavalin A; Inflammation; Interleukin-4; Janus Kinase 3; Lymphocytes; Male; Naloxone; Pain; Pro-Opiomelanocortin; Quaternary Ammonium Compounds; Rats; Rats, Wistar; RNA, Messenger; STAT1 Transcription Factor; STAT3 Transcription Factor

Microinjection of opioids into the ventrolateral periaqueductal gray (vlPAG) produces antinociception in part by binding to mu-opioid receptors (MOPrs). Although both high and low efficacy agonists produce antinociception, low efficacy agonists such as morphine produce limited MOPr internalization suggesting that MOPr internalization and signaling leading to antinociception are independent. This hypothesis was tested in awake, behaving rats using DERM-A594, a fluorescently labeled dermorphin analog, and internalization blockers. Microinjection of DERM-A594 into the vlPAG produced both antinociception and internalization of DERM-A594. Administration of the irreversible opioid receptor antagonist beta-chlornaltrexamine (beta-CNA) prior to DERM-A594 microinjection reduced both the antinociceptive effect and the number of DERM-A594 labeled cells demonstrating that both effects are opioid receptor-mediated. Pretreatment with the internalization blockers dynamin dominant-negative inhibitory peptide (dynamin-DN) and concanavalinA (ConA) attenuated both DERM-A594 internalization and antinociception. Microinjection of dynamin-DN and ConA also decreased the antinociceptive potency of the unlabeled opioid agonist dermorphin when microinjected into the vlPAG as demonstrated by rightward shifts in the dose-response curves. In contrast, administration of dynamin-DN had no effect on the antinociceptive effect of microinjecting the GABA(A) receptor antagonist bicuculline into the vlPAG. The finding that dermorphin-induced antinociception is attenuated by blocking receptor internalization indicates that key parts of opioid receptor-mediated signaling depend on internalization.

Topics: Analgesics, Opioid; Animals; Bicuculline; Concanavalin A; Dynamins; Fluorescent Dyes; GABA-A Receptor Antagonists; Male; Microinjections; Naltrexone; Neurons; Opioid Peptides; Pain; Pain Measurement; Peptides; Periaqueductal Gray; Rats; Rats, Sprague-Dawley; Receptors, Opioid, mu

The mechanisms of the analgesic action of carbamazepine and oxcarbazepine, in particular the role of opioid receptors, have not been established precisely. The systemic effects of naloxone, an opioid receptor antagonist, on the antihyperalgesic effects of carbamazepine and oxcarbazepine were examined in the model of inflammatory hyperalgesia induced by the intraplantar (i.pl.) administration of concanavaline A (Con A, 0.8 mg/paw) into the rat hind paw. Naloxone (3 mg/kg; i.p.) did not alter the antihyperalgesic effects of either carbamazepine or oxcarbazepine. These results indicate that the opioid system of pain modulation does not play a significant role in the antihyperalgesic effects of carbamazepine and oxcarbazepine.

Topics: Analgesics, Non-Narcotic; Animals; Anticonvulsants; Carbamazepine; Concanavalin A; Hyperalgesia; Male; Naloxone; Narcotic Antagonists; Oxcarbazepine; Pain; Rats; Rats, Wistar

The anticonvulsant carbamazepine was recently shown to possess local peripheral antinociceptive properties. In this study, we investigated whether alpha2-adrenergic receptors are involved in the local peripheral antihyperalgesic effects of carbamazepine and determined the type of interaction between carbamazepine and clonidine, an alpha2-adrenoceptor agonist. Intraplantar (i.pl.) coadministration of either carbamazepine (100-1000 nmol/paw) or clonidine (1.9-3.7 nmol/paw) with the proinflammatory compound concanavalin A (Con A; 0.8 mg/paw) caused a significant dose- and time-dependent reduction of the difference between the forces exerted by a rat's hind paws in a modified paw-pressure test. The coadministration of 260 and 520 nmol/paw (i.pl.) yohimbine, an alpha2-adrenoceptor antagonist, with carbamazepine, significantly depressed the local antihyperalgesic effect in a dose- and time-dependent manner whereas yohimbine by itself did not have any effect. The administration of a mixture of carbamazepine and clonidine at fixed dose fractions (1/4, 1/2 and 3/4) of ED50 caused a significant and dose-dependent reduction of Con A-induced hyperalgesia. Isobolographic analysis revealed an additive interaction. These results suggest that alpha2-adrenoceptors play a role in the local peripheral antihyperalgesic effects of carbamazepine and that local peripheral coadministration of carbamazepine with clonidine results in an additive antihyperalgesic effect.

Topics: Adrenergic alpha-2 Receptor Antagonists; Adrenergic alpha-Antagonists; Analgesics, Non-Narcotic; Animals; Carbamazepine; Concanavalin A; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Synergism; Drug Therapy, Combination; Hindlimb; Hyperalgesia; Inflammation; Injections; Male; Pain; Pain Measurement; Rats; Rats, Wistar; Receptors, Adrenergic, alpha-2; Time Factors; Yohimbine

This study investigated whether carbamazepine could produce local peripheral antinociception in a rat model of inflammatory mechanical hyperalgesia, and whether adenosine receptors are involved. Carbamazepine (100-1000 nmol/paw) co-administrated with a pro-inflammatory compound, concanavalin A, into the hind paw caused a significant dose- and time-dependent anti-hyperalgesia. Coadministration of caffeine (250-1000 nmol/paw), a nonselective adenosine-receptor antagonist, as well as DPCPX (10-30 nmol/paw), a selective adenosine A(1)-receptor antagonist, with carbamazepine, significantly depressed its anti-hyperalgesic effect. Drugs injected into the contralateral hind paw did not produce significant effects. These results suggest that carbamazepine produces local peripheral anti-hyperalgesia via peripheral adenosine A(1) receptors.

Topics: Analgesics; Animals; Caffeine; Carbamazepine; Concanavalin A; Disease Models, Animal; Dose-Response Relationship, Drug; Hyperalgesia; Inflammation; Male; Pain; Rats; Rats, Wistar; Receptor, Adenosine A1; Time Factors; Touch; Xanthines

The inhibitory actions of etodolac on prostaglandin (PG) E2 biosynthesis, active oxygen generation and bradykinin formation were compared with those of indomethacin, diclofenac Na, piroxicam, naproxen, ketoprofen and aspirin. The inhibitory action (IC50 5.35 x 10(-8) M) of etodolac on PGE2 biosynthesis in rabbit articular chondrocytes stimulated by interleukin-1 (IL-1) beta was about 1/5 that of indomethacin. The inhibitory action of etodolac on spontaneous PGE2 biosynthesis in rabbit gastric epithelial cells (RGEs) (IC50 2.27 x 10(-5) M) and Madin-Darby canine kidney cells (MDCKs) (IC50 4.54 x 10(-7) M) was much less than that in rabbit articular chondrocytes stimulated by IL-1 beta and about 1/19 and 1/9 that of indomethacin in rabbit gastric epithelial cells (RGEs) and Madin-Darby canine kidney cells (MDCKs), respectively. The inhibitory action of etodolac on active oxygen generation was similar to that of indomethacin and piroxicam, and more potent than that of naproxen, ketoprofen and aspirin. The inhibitory action of etodolac on bradykinin formation was the most potent among the seven anti-inflammatory drugs tested. Both etodolac and bromelain inhibited the inflammatory pain in concanavalin A-treated paws of rats in a dose-dependent manner, but indomethacin did not. These results indicate that etodolac is an anti-inflammatory drug which suppress IL-1 beta-stimulated PGE2 biosynthesis in rabbit articular chondrocytes, active oxygen generation and bradykinin formation. It has less suppressive action against spontaneous PGE2 biosynthesis in RGEs and MDCKs. Thus, etodolac is considered to be a safe anti-inflammatory drug for clinical use.

Topics: Animals; Aspirin; Bradykinin; Bromelains; Cartilage, Articular; Cell Line; Concanavalin A; Depression, Chemical; Diclofenac; Dinoprostone; Dogs; Etodolac; Gastric Mucosa; Guinea Pigs; Indomethacin; Interleukin-1; Ketoprofen; Kidney; Naproxen; Oxygen; Pain; Piroxicam; Rabbits; Rats

We previously demonstrated that plaque-forming cell (PFC) production in the spleen of mice immunized with sheep red blood cells (SRBC) was enhanced by pain stimulation. This phenomenon was due to activation of antigen nonspecific L3T4-/Lyt-2- T lymphocytes (double-negative T cells) by the beta-adrenergic action of endogenous catecholamines released from the adrenal gland after pain stimulation. Further study also demonstrated that interleukin-2 (IL-2) production of spleen cells was enhanced in mice by pain stimulation. In this study spleen cells of BALB/c mice were cultured with Con A and SRBC, respectively, and the IL-2 level was measured by incorporation of 3H-thymidine into CTLL-2 cells during culture for 24 hours. Interleukin-2 production of spleen cells from mice given pain stimulation was significantly increased compared with spleen cells of normal mice. The IL-2 production of spleen cells of normal mice was also markedly enhanced by the mixed culture with spleen cells from pain-stimulated mice. Enhancement of IL-2 production in the spleen cells of mice given pain stimulation did not occur with anti-Thy-1.2 antibody and complement treatment, but production was maintained by treatment with anti-L3T4 antibody and complement. These data suggest that the enhanced production of IL-2 in mice given pain stimulation resulted from the activation of L3T4- T cells by endogenous catecholamines released from the adrenal gland after pain stimulation. It can be assumed that activated L3T4- T cells interact with antigen-specific L3T4+ T cells and lead to enhanced IL-2 production.

Topics: Animals; Concanavalin A; Epinephrine; Erythrocytes; Interleukin-2; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Pain; Sheep; Spleen; T-Lymphocytes; T-Lymphocytes, Helper-Inducer

The influence of Met-enkephalin on mitogenic stimulation of mouse splenocytes was investigated. Met-enkephalin (ME) was shown to suppress proliferation induced by Concanavalin A and activate proliferation induced by Staphylococcus enterotoxin A. Both effects were revealed at low (down to 10(-14) M) concentration of pentapeptide. Naloxone reversed ME influence on cell activation. The number of receptors for naloxone was shown to increase up to 2.5-fold during mitogenic activation. The difference in expression of various types of opioid receptors at mitogenic stimulation was demonstrated by ligand displacement experiments.

Topics: Animals; Binding, Competitive; Concanavalin A; Diprenorphine; Enkephalin, Methionine; Enterotoxins; Female; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Naloxone; Pain; Receptors, Opioid; Receptors, Opioid, delta; Receptors, Opioid, mu; Sensory Thresholds; Spleen