Search

Background and Purpose: Spinal voltage-gated calcium channels (VGCCs) are pivotal regulators of painful and inflammatory alterations, representing attractive therapeutic targets. We examined the effects of epidural administration of the P/Q- and N-type VGCC blockers Tx3-3 and Phα1β, respectively, isolated from the spider Phoneutria nigriventer, on symptomatic, inflammatory and functional changes allied to mouse cyclophosphamide (CPA)-induced haemorrhagic cystitis (HC). The effects of P. nigriventer-derived toxins were compared with those displayed by MVIIC and MVIIA, extracted from the cone snail Conus magus., Experimental Approach: HC was induced by a single i.p. injection of CPA (300 mg·kg(-1) ). Dose- and time-related effects of spinally administered P/Q and N-type VGCC blockers were assessed on nociceptive behaviour and macroscopic inflammation elicited by CPA. The effects of toxins were also evaluated on cell migration, cytokine production, oxidative stress, functional cystometry alterations and TRPV1, TRPA1 and NK1 receptor mRNA expression., Key Results: The spinal blockage of P/Q-type VGCC by Tx3-3 and MVIIC or N-type VGCC by Phα1β attenuated nociceptive and inflammatory events associated with HC, including bladder oxidative stress and cytokine production. CPA produced a slight increase in bladder TRPV1 and TRPA1 mRNA expression, which was reversed by all the toxins tested. Noteworthy, Phα1β strongly prevented bladder neutrophil migration, besides HC-related functional alterations, and its effects were potentiated by co-injecting the selective NK1 receptor antagonist CP-96345., Conclusions and Implications: Our results shed new light on the role of spinal P/Q and N-type VGCC in bladder dysfunctions, pointing out Phα1β as a promising alternative for treating complications associated with CPA-induced HC., (© 2014 The British Pharmacological Society.)

Background and Purpose: ATP is released in response to cellular damage, and P2X7 receptors have an essential role in the onset and maintenance of pathological changes. Haemorrhagic cystitis (HC) is a well-known adverse effect of therapy with cyclophosphamide used for the treatment of many solid tumours and autoimmune conditions. Here we have evaluated the role of P2X7 receptors in a model of HC induced by cyclophosphamide., Experimental Approach: Effects of pharmacological antagonism or genetic deletion of P2X7 receptor on cyclophosphamide-induced HC in mice was assessed by nociceptive and inflammatory measures. In addition, the presence of immunoreactive P2X7 receptors was assessed by immunohistochemistry., Key Results: Pretreatment with the selective P2X7 receptor antagonist A-438079 or genetic ablation of P2X7 receptors reduced nociceptive behaviour scores in the HC model. The same strategies decreased both oedema and haemorrhage indices, on macroscopic or histological evaluation. Treatment with A-438079 decreased the staining for c-Fos in the lumbar spinal cord and brain cortical areas. Treatment with A-438079 also prevented the increase of urinary bladder myeloperoxidase activity and macrophage migration induced by cyclophosphamide and reduced the tissue levels of IL-1β and TNF-α. Finally, P2X7 receptors were markedly up-regulated in the bladders of mice with cyclophosphamide-induced HC., Conclusions and Implications: P2X7 receptors were significantly involved in a model of HC induced by cyclophosphamide. Pharmacological inhibition of these receptors might represent a new therapeutic option for this pathological condition., (© 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.)

Background and Purpose: Resolution of inflammation is mediated by endogenous molecules with anti-inflammatory and pro-resolving activities and they have generated new possibilities for the treatment of inflammatory diseases. Here, we have investigated the possible anti-hyperalgesic effects of two lipids, aspirin-triggered resolvin D1 (AT-RvD1) and its precursor, 17(R)-hydroxy-4Z,7Z,10Z,13Z,15E,17R,19Z-docosahexaenoic acid (17(R)HDoHE)., Experimental Approach: The anti-hyperalgesic effects of both lipid mediators were evaluated, using mechanical and thermal stimuli, at different time-points in adjuvant-induced arthritis in rats. Cytokine levels were measured, and immunohistochemistry and real-time PCR for pro-inflammatory mediators were also performed., Key Results: The precursor of resolvin D series, 17(R)HDoHE, given systemically, inhibited the development and the maintenance of mechanical hyperalgesia in acute inflammation. Such effects were likely to be associated with modulation of both NF-κB and COX-2 in dorsal root ganglia and spinal cord. 17(R)HDoHE was also effective against sub-chronic pain. Unexpectedly, repeated treatment with 17(R)HDoHE did not modify paw and joint oedema in the sub-chronic model, while joint stiffness was prevented. Notably, AT-RvD1 exhibited marked anti-hyperalgesic effects in acute inflammation when given systemically. The efficacy of long-term treatment with either 17(R)HDoHE or AT-RvD1 was partly related to decreased production of TNF-α and IL-1β in rat hind paw., Conclusions and Implications: Our findings provide fresh evidence for the anti-hyperalgesic properties of 17(R)HDoHE and its pro-resolution metabolite AT-RvD1. Such lipid mediators might be useful for treating pain associated with acute or chronic inflammation. LINKED ARTICLE This article is commented on by Xu and Ji, pp. 274-277 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2011.01348.x., (© 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.)

Background and Purpose: The effects of systemic treatment with indomethacin-loaded nanocapsules (IndOH-NC) were compared with those of free indomethacin (IndOH) in rat models of acute and chronic oedema., Experimental Approach: The following models of inflammation were employed: carrageenan-induced acute oedema (measured between 30 min and 4 h), sub-chronic oedema induced by complete Freund's adjuvant (CFA) (determined between 2 h and 72 h), and CFA-induced arthritis (oedema measured between 14 and 21 days)., Key Results: IndOH or IndOH-NC produced equal inhibition of carrageenan-elicited oedema. However, IndOH-NC was more effective in both the sub-chronic (33 +/- 4% inhibition) and the arthritis (35 +/- 2% inhibition) model of oedema evoked by CFA, when compared with IndOH (21 +/- 2% and 14 +/- 3% inhibition respectively) (P < 0.01). In the CFA arthritis model, treatment with IndOH-NC markedly inhibited the serum levels of the pro-inflammatory cytokines tumour necrosis factor alpha and IL-6 (by 83 +/- 8% and 84 +/- 11% respectively), while the levels of the anti-inflammatory cytokine IL-10 were significantly increased (196 +/- 55%). The indices of gastrointestinal damage in IndOH-NC-treated animals were significantly less that those after IndOH treatment (58 +/- 16%, 72 +/- 6% and 69 +/- 2%, for duodenum, jejunum and ileum respectively)., Conclusions and Implications: IndOH-NC produced an increased anti-inflammatory efficacy in long-term models of inflammation, allied to an improved gastrointestinal safety. This formulation might represent a promising alternative for treating chronic inflammatory diseases, with reduced undesirable effects.

1. The effect of endogenous glucocorticoid hormones on the expression of rat B(1) receptors was examined by means of molecular and pharmacological functional approaches. 2. Rats were adrenalectomized (ADX), and 7 days after this procedure the intradermal injection of B(1) receptor agonist des-Arg(9)-BK produced a significant increase in the paw volume, while only a weak effect was observed in sham-operated animals. A similar increase in the contractile responses mediated by B(1) agonist des-Arg(9)-BK was also observed in the rat portal vein in vitro. 3. Chemical ADX performed with mitotane (a drug that reduces corticosteroid synthesis) produced essentially the same up-regulation of B(1) receptors as that observed in ADX rats. 4. The modulation of B(1) receptor expression was evaluated by ribonuclease protection assay, employing mRNA obtained from the lungs and paw of ADX rats. 5. Additionally, both paw oedema and contraction of portal vein mediated by B(1) agonist des-Arg(9)-BK in ADX rats, were markedly inhibited by treatment with dexamethasone, or COX-2 inhibitor meloxican, or with the NF-kappaB inhibitor PDTC. Interestingly, the same degree of inhibition was achieved when the animals were treated with a combination of submaximal doses of dexamethasone and PDTC. 6. The involvement of NF-kappaB pathway was further confirmed by mobility shift assay using nuclear extracts from lung, paw and heart of ADX rats. It was also confirmed that the treatment of ADX rats with dexamethasone, PDTC or dexamethasone plus PDTC completely inhibit NF-kappaB activation caused by absence of endogenous glucucorticoid. 7. Together, the results of the present study provide, for the first time, molecular and pharmacological evidence showing that B(1) kinin receptor expression can be regulated through endogenous glucocorticoids by a mechanism dependent on NF-kappaB pathway. Clinical significance of the present findings stem from evidence showing the importance of B(1) kinin receptors in the mediation of inflammatory and pain related responses.

1. Intradermal (i.d.) injection of cytokines, IL-1beta and TNFalpha (5 ng, 60 and 30 min prior) produces a rapid onset up-regulation of des-Arg9-BK-mediated rat paw oedema. Here we analyse the mechanisms involved in des-Arg9-BK-induced oedema in animals pre-treated with IL-1beta or TNFalpha. 2. Co-injection of anti-IL-1beta, anti-TNFalpha and anti-IL-8 (50 ng) significantly inhibited des-Arg9-BK-induced oedema in animals pre-treated with IL-1beta (65, 37 and 42%) or TNFalpha (39, 64, 25%). IL-1 receptor antagonist (IRA, 100 microg) or IL-10 (10 ng) inhibited the oedema caused by des-Arg9-BK, in rats that had received either IL-1beta (67 and 63%) or TNFalpha (46 and 35%). 3. Co-injection of the PKC inhibitors, staurosporine (10 nmol) or RO 318220 (30 nmol) inhibited des-Arg9-BK-induced paw oedema (44 and 42% for IL-1beta and, 53 and 30% for TNFalpha, respectively). Genistein (tyrosine kinase inhibitor, 2.5 mg kg-1, s.c.) or PD 098059 (MAP-kinase inhibitor, 30 nmol) produced marked inhibition of des-Arg9-BK-induced oedema (58 and 39% for IL-1beta and 31 and 35% for TNFalpha respectively). 4. The NF-kappaB inhibitors TLCK (2 mg kg-1, i.p.) and PDCT (100 mg kg-1, i.p.) significantly inhibited the oedema of des-Arg9-BK in IL-1beta (27 and 83%) or TNFalpha (28 and 80%) pre-treated animals. 5. It is concluded that up-regulation of B1 receptors modulated by IL-1beta or TNFalpha involves the release of other cytokines, activation of PKC and tyrosine kinase pathways, co-ordinated with the activation of MAP-kinase and nuclear factor kappaB, reinforcing the view that B1 receptors may exert a pivotal role in modulating chronic inflammatory processes.

1. The present study was designed to investigate the influence of long-term systemic treatment with Mycobacterium bovis bacillus Calmette-Guérin (BCG, 1 dose per animal, containing 6 x 10(4) colony-forming-units (CFu), 5 to 75 days beforehand) on oedema formation induced by intradermal injection of B1 and B2 selective agonists. The interaction between the B1 agonist des-Arg9-bradykinin and bradykinin was also investigated. 2. Intradermal injection (i.d.) of the B2 selective agonist tyrosine8-bradykinin (1-10 nmol) in naive (saline pretreated) animals, or in animals that had received BCG (30 days beforehand), caused dose-related and very similar oedema formation (ED50; 1.1 and 1.0 nmol/paw, respectively). I.d. injection of the selective B1 agonists des-Arg9-bradykinin (100 nmol) or des-Arg10-kallidin in naive animals caused very little paw oedema (0.04 +/- 0.06 and 0.07 +/- 0.02 ml, respectively, n = 5). However, i.d. injection of des-Arg9-bradykinin (10-300 nmol) or des-Arg10-kallidin (3-100 nmol) in animals pretreated with BCG, 30 days previously, resulted in dose-related and marked oedema formation, with mean ED50 values of 20.1 and 5.5 nmol/paw, respectively. 3. Oedema caused by i.d. injection of des-Arg9-bradykinin (100 nmol/paw) in rats pretreated with BCG was evident 5 days after treatment, reaching the maximum 30 days later, remaining stable for up to 45 days, and reduced markedly at 75 days. 4. The i.d. co-injection of the selective B1 antagonists des-Arg9[Leu8]-bradykinin (200 nmol), des-Arg10[Leu9]-bradykinin (30 nmol) and des-Arg9-NPC 17731 (30 nmol) significantly (18 +/- 3, 34 +/- 2 and 56 +/- 4%, respectively) prevented the paw oedema caused by i.d. injection of des-Arg9-bradykinin (100 nmol) in rats treated with BCG. These effects were selective, because the i.d. injection of the B1 selective antagonist des-Arg10[Leu9]-kallidin (30 nmol), at the same dose that consistently antagonized des-Arg9-bradykinin (100 nmol)-mediated paw oedema, had no significant effect against tyrosine8-bradykinin (3 nmol)-induced oedema in animals that had been treated previously with BCG. On the other hand, the i.d. co-injection of the selective B2 antagonist, Hoe 140 (10 nmol) at a dose which markedly inhibited tyrosine8-bradykinin (3 nmol)-induced oedema by 55 +/- 4%, did not significantly affect des-Arg9-bradykinin-induced paw oedema in animals pretreated with BCG. 5. Treatment of animals with dexamethasone (0.5 mg kg-1, s.c.) every 24 h, from day 0 to day 30, inhibited significantly (67 +/- 4%) the oedema caused by des-Arg9-bradykinin (100 nmol), but did not affect the paw oedema caused by tyrosine8-bradykinin (3 nmol) in animals pretreated with BCG. 6. Indomethacin (2 mg kg-1, i.p.), administered 1 h before experiments, significantly inhibited des-Arg9-bradykinin (100 nmol)-induced oedema formation, and, to a lesser extent, the paw oedema caused by tyrosine8-bradykinin (3 nmol) (44 +/- 4 and 20 +/- 4%, respectively). 7. These findings show that the long-term systemic treatment of rats with BCG promoted a time-dependent and consistent paw oedema formation to B1 agonists, des-Arg9-bradykinin and des-Arg10-kallidin, leaving responses to the B2 agonist tyrosine8-bradykinin unaffected. The upregulation of B1 receptors after BCG treatment was inhibited by dexamethasone, suggesting the possible involvement of de novo protein synthesis. Finally, our results also show that in BCG-treated animals, the B1 agonist des-Arg9-bradykinin interacts in a synergistic manner with bradykinin. Therefore, both B1 and B2 kinin receptors appear to play a relevant role in modulating chronic inflammatory processes.

1. The effect of pretreatment with bacterial endotoxin (LPS, 10 micrograms, i.v., 24 h) on the bradykinin B1 and B2 receptor-induced oedema in the rat paw, and the interaction of B1-mediated responses with other inflammatory mediators, was investigated. 2. Intraplantar (i.pl.) injection of the selective B1 agonist, des-Arg9-BK (DABK, 100 nmol) in naive animals pretreated with the angiotensin converting enzyme inhibitor, captopril caused a small increase in paw volume (0.04 +/- 0.003 ml, mean +/- s.e. mean, n = 6), while the B2-selective agonist, tyrosine8-bradykinin (T-BK, 3 nmol) induced marked oedema (0.36 +/- 0.02 ml). However, i.pl. injection of DABK (3-300 nmol) in rats pretreated with LPS (24 h beforehand) resulted in a marked dose- and time-related increase in paw volume, with mean ED50 of 24.1 nmol. In contrast, oedema caused by T-BK (3 nmol) was reduced by 79 +/- 4% in animals treated with LPS when compared with naive animals. 3. Oedema caused by prostaglandin E2 (PGE2, 10 nmol) was unaffected by LPS treatment, while oedema induced by histamine (100 nmol), 5-hydroxytryptamine (5-HT, 10 nmol) and substance P (SP, 3 nmol) was reduced (P < 0.05). 4. The selective B1 antagonist, des-Arg9[Leu8]-BK (100-300 nmol), produced dose-dependent inhibition of DABK (100 nmol)-induced paw oedema in LPS-treated animals with mean IC50 of 134 nmol, while the selective B2 antagonists, Hoe 140 and NPC 17731 (each 10 nmol), had no effect. 5. Treatment of animals with dexamethasone (0.5 mg kg-1, s.c.) 24 or 48 h prior to LPS injection resulted in a graded inhibition of DABK (100 nmol)-induced oedema formation (58 +/- 3 and 82 +/- 2%, respectively), and almost reversed to control value oedema formation induced by T-BK (3 nmol) in LPS-pretreated rats. Cycloheximide (1 mg kg-1, s.c.) or indomethacin (2 mg kg-1, i.p.) pretreatment 24 and 1 h prior to LPS injection, respectively, markedly inhibited DABK (100 nmol)-induced paw oedema (98 +/- 2 and 50 +/- 4%, respectively). 6. Intraplantar injection of submaximal dose of DABK (10 nmol) in LPS-treated rats produced modest paw oedema (0.09 +/- 0.03 ml). However, i.pl. injections of PGE2, prostacyclin (PGI2), calcitonin-gene-related peptide (CGRP), SP, 5-HT, or platelet activating factor (PAF) (each 1 nmol), which alone caused little or no paw oedema, resulted in a potentiation of the DABK-induced oedema. The increases in paw volume (in ml) were: PGE2 + DABK (0.31 +/- 0.03), PGI2 + DABK (0.39 +/- 0.02), CGRP+DABK (0.35 +/- 0.04), DABK+SP (0.33 +/- 0.04), DABK + 5-HT (0.40 +/- 0.02) and DABK+PAF (0.38 +/- 0.016) ml. In contrast, histamine (1 nmol) was ineffective in potentiating the response to DABK. 7. The selective B1 receptor antagonist, DALBK (100-300 nmol), produced dose-dependent inhibition of paw oedema potentiation induced by co-injection of DABK and other mediators with mean ID50S (nmol) of: 180, 160, 139 and 135 in the presence of PGE2, PGI2, SP and 5-HT, respectively. 8. These results demonstrate that DABK-induced increase in paw volume in LPS-treated rats is probably mediated by induction of B1 receptors, associated with downregulation of B2 receptors. The induction of B1 receptors by LPS is sensitive to dexamethasone and cycloheximide treatment and requires activation of cyclo-oxygenase pathway. In addition, B1 receptors, when upregulated following LPS treatment, can interact in a synergistic manner with several inflammatory mediators such as PGI2, PGE2, CGRP, PAF and 5-HT. Such results indicate that induction of the B1 receptor might have a significant pathophysiological role in modulating chronic inflammatory diseases.

1. The mechanisms involved in bradykinin (BK)-induced oedema in the rat paw as well as the interactions between BK and several inflammatory mediators, have been investigated. 2. Intraplantar injection of BK (1 nmol/paw) in rats pretreated with captopril (5 mg kg-1, s.c.) caused a small amount of oedema formation (0.17 +/- 0.05 ml). Des-Arg9-BK (DABK, a selective B1 receptor agonist) up to 300 nmol/paw caused minimal oedema (0.03 +/- 0.01 ml). 3. Co-administration of prostaglandin E2 (PGE2), prostaglandin I2 (PGI2), calcitonin gene-related peptide (CGRP), 5-hydroxytryptamine (5-HT), substance P (SP) or platelet activating factor (PAF) (1 pmol-1 nmol/paw) with BK (1 nmol/paw) dose-dependently potentiated BK-induced paw oedema. The rank order of potency (mean ED50, pmol/paw) for this effect was: SP (8.1) > PAF (13.7) > PGI2 (20.5) > 5-HT (23.8) > CGRP (25.7) > PGE2 (52.0). Co-administration of BK with the various inflammatory mediators resulted in maximal paw oedemas (ml) of: PGE2 (0.71 +/- 0.02); PGI2 (0.66 +/- 0.02); 5-HT (0.65 +/- 0.01); SP (0.63 +/- 0.05); CGRP (0.60 +/- 0.05) and PAF (0.47 +/- 0.02) ml. Histamine (up to 1 nmol/paw) was ineffective in potentiating the response to BK. 4. Hoe 140 or NPC 17731 (two selective B2 receptor antagonists, 0.1-3 nmol/paw) produced dose-dependent inhibition of paw oedema potentiation induced by co-injection of BK with other mediators with the following mean ID50s (nmol/paw): Hoe 140-1.4; 1.3; 1.5 and 1.1 and NPC 17731-1.0; 1.0; 0.9 and 0.7; in the presence of PGE2, PGI2, CGRP and SP, respectively. The selective B1 receptor antagonist des-Arg9 [Leu8]-BK (DALBK, up to 300 nmol/paw) had no effect.5. Daily intraplantar injections of BK (10 nmol/paw) once a day for 7 consecutive days caused a progressive and complete desensitization of the paw oedema, which was specific for BK, since paw oedema induced by PAF, PGE2, SP or histamine was not affected. In addition, the oedema caused by BK in the paw desensitized to the peptide was almost completely reversed if BK was co-injected with PGE2, PGI2 or SP (1 nmol/paw). Injection of PGE2 or SP (10 nmol/paw) together with the first BK injection (1O nmol/paw), partially prevented BK-induced desensitization.6. When animals were completely desensitized to BK, DABK (100nmol/paw) caused paw oedema(0.25 +/- 0.03 ml) which was consistently blocked by the B1 receptor antagonist, DALBK (100 nmol/paw).7. Treatment of animals with dexamethasone (0.5 mg kg-1, s.c., 24 h previously) antagonized paw oedema induced by DABK (100 nmol/paw) in desensitized paws, but not that induced by BK (3 nmol/paw) in naive paws. The steroid also prevented the recovery of oedema seen after co-injection of BK with PGE2 or PGI2 (1 nmol/paw) in desensitized paws.8. These results suggest that both B, and B2 receptors are involved in BK-induced rat paw oedema. The B2 receptors are constitutive, but induction of expression of B, receptors seems to occur only after complete desensitization of the paw to BK. In addition, very low doses of inflammatory mediators markedly potentiate BK-induced paw oedema and can attenuate BK-induced paw oedema desensitization.Such mechanisms may be relevant for the manifestation of acute and chronic inflammatory processes.