scholarly journals Neurokinin-1 Receptor Antagonist Treatment in Polymicrobial Sepsis: Molecular Insights

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Akhil Hegde ◽  
Yung-Hua Koh ◽  
Shabbir M. Moochhala ◽  
Madhav Bhatia

Neurokinin-1 receptor blocking has been shown to be beneficial against lung injury in polymicrobial sepsis. In this paper, we evaluated the possible mediators and the mechanism involved. Mice were subjected to cecal ligation and puncture (CLP-) induced sepsis or sham surgery. Vehicle or SR140333 [1 mg/kg; subcutaneous (s.c.)] was administered to septic mice either 30 min before or 1 h after the surgery. Lung tissue was collected 8 h after surgery and further analyzed. CLP alone caused a significant increase in the activation of the transcription factors, protein kinase C-α, extracellular signal regulated kinases, neurokinin receptors, and substance P levels in lung when compared to sham-operated mice. SR140333 injected pre- and post surgery significantly attenuated the activation of transcription factors and protein kinase C-αand the plasma levels of substance P compared to CLP-operated mice injected with the vehicle. In addition, GR159897 (0.12 mg/kg; s.c.), a neurokinin-2 receptor antagonist, failed to show beneficial effects. We conclude that substance P acting via neurokinin-1 receptor in sepsis initiated signaling cascade mediated mainly by protein kinase C-α,led to NF-κB and activator protein-1 activation, and further modulated proinflammatory mediators.

2001 ◽  
Vol 280 (5) ◽  
pp. C1097-C1106 ◽  
Author(s):  
Olivier Déry ◽  
Kathryn A. Defea ◽  
Nigel W. Bunnett

An understanding of the mechanisms that regulate signaling by the substance P (SP) or neurokinin 1 receptor (NK1-R) is of interest because of their role in inflammation and pain. By using activators and inhibitors of protein kinase C (PKC) and NK1-R mutations of potential PKC phosphorylation sites, we determined the role of PKC in desensitization of responses to SP. Activation of PKC abolished SP-induced Ca2+ mobilization in cells that express wild-type NK1-R. This did not occur in cells expressing a COOH-terminally truncated NK1-R (NK1-Rδ324), which may correspond to a naturally occurring variant, or a point mutant lacking eight potential PKC phosphorylation sites within the COOH tail (NK1-R Ser-338, Thr-339, Ser-352, Ser-387, Ser-388, Ser-390, Ser-392, Ser-394/Ala, NK1-RKC4). Compared with wild-type NK1-R, the t ½ of SP-induced Ca2+mobilization was seven- and twofold greater in cells expressing NK1-Rδ324 and NK1-RKC4, respectively. In cells expressing wild-type NK1-R, inhibition of PKC caused a 35% increase in the t ½ of SP-induced Ca2+mobilization. Neither inhibition of PKC nor receptor mutation affected desensitization of Ca2+ mobilization to repeated challenge with SP or SP-induced endocytosis of the NK1-R. Thus PKC regulates SP-induced Ca2+ mobilization by full-length NK1-R and does not regulate a naturally occurring truncated variant. PKC does not mediate desensitization to repeated stimulation or endocytosis of the NK1-R.


2000 ◽  
Vol 278 (4) ◽  
pp. R937-R946 ◽  
Author(s):  
Ulla C. Kopp ◽  
Donna M. Farley ◽  
Michael Z. Cicha ◽  
Lori A. Smith

Increased renal pelvic pressure or bradykinin increases afferent renal nerve activity (ARNA) via PGE2-induced release of substance P. Protein kinase C (PKC) activation increases ARNA, and PKC inhibition blocks the ARNA response to bradykinin. We now examined whether bradykinin mediates the ARNA response to increased renal pelvic pressure by activating PKC. In anesthetized rats, the ARNA responses to increased renal pelvic pressure were blocked by renal pelvic perfusion with the bradykinin B2-receptor antagonist HOE 140 and the PKC inhibitor calphostin C by 76 ± 8% ( P < 0.02) and 81 ± 5% ( P < 0.01), respectively. Renal pelvic perfusion with 4β-phorbol 12,13-dibutyrate (PDBu) to activate PKC increased ARNA 27 ± 4% and renal pelvic release of PGE2 from 500 ± 59 to 1,113 ± 183 pg/min and substance P from 10 ± 2 to 30 ± 2 pg/min (all P < 0.01). Indomethacin abolished the increases in substance P release and ARNA. The PDBu-mediated increase in ARNA was also abolished by the substance P-receptor antagonist RP 67580. We conclude that bradykinin contributes to the activation of renal pelvic mechanosensitive neurons by activating PKC. PKC increases ARNA via a PGE2-induced release of substance P.


2001 ◽  
Vol 280 (1) ◽  
pp. H377-H383 ◽  
Author(s):  
Joon Huh ◽  
Garrett J. Gross ◽  
Hiroshi Nagase ◽  
Bruce T. Liang

The objective of the present study was to investigate the role of δ1-opioid receptors in mediating cardioprotection in isolated chick cardiac myocytes and to investigate whether protein kinase C and mitochondrial ATP-sensitive K+(KATP) channels act downstream of the δ1-opioid receptor in mediating this beneficial effect. A 5-min preexposure to the selective δ1-opioid receptor agonist (−)-TAN-67 (1 μM) resulted in less myocyte injury during the subsequent prolonged ischemia compared with untreated myocytes. 7-Benzylidenenaltrexone, a selective δ1-opioid receptor antagonist, completely blocked the cardioprotective effect of (−)-TAN-67. Naltriben methanesulfonate, a selective δ2-opioid receptor antagonist, had only a slight inhibitory effect on (−)-TAN-67-mediated cardioprotection. Nor-binaltorphimine dihydrochloride, a κ-opioid receptor antagonist, did not affect (−)-TAN-67-mediated cardioprotection. The protein kinase C inhibitor chelerythrine and the KATP channel inhibitors glibenclamide, a nonselective KATP antagonist, and 5-hydroxydecanoic acid, a mitochondrial selective KATPantagonist, reversed the cardioprotective effect of (−)-TAN-67. These results suggest that the δ1-opioid receptor is present on cardiac myocytes and mediates a potent cardioprotective effect via protein kinase C and the mitochondrial KATP channel.


1993 ◽  
Vol 71 (9) ◽  
pp. 639-644 ◽  
Author(s):  
Nora Goren ◽  
Claudia Perez Leiros ◽  
Leonor Sterin-Borda ◽  
Enri Borda

Two populations of histaminergic H1 receptors with distinct high and low affinity binding sites were characterized by the specific H1 receptor antagonist [3H]mepyramine in autoimmune myocardium. No saturable binding of the radiolabelled H1 antagonist was observed in normal myocardium. Reaction of autoimmune myocardium with specific H1 agonist (2-thiazolyl-ethylamine (ThEA)) triggered positive inotropy and negative chronotropy, which were inhibited by mepyramine. Inhibitors of phospholipase C and protein kinase C attenuated both the inotropic and chronotropic effects of ThEA, suggesting the participation of phosphoinositide hydrolysis in this phenomenon. The latter was verified by measurement of polyphosphoinositide hydrolysis in autoimmune myocardium following the reaction of ThEA with histaminergic H1 receptors. We conclude that functional H1 histaminergic receptors could involve a distinctive mechanism operating in autoimmune myocardium as a result of cardiac antigen immunization.Key words: histamine, H1 receptors, myocarditis, autoimmunity.


1988 ◽  
Vol 256 (2) ◽  
pp. 677-680 ◽  
Author(s):  
H Sugiya ◽  
J W Putney

Substance P-induced inositol trisphosphate (InsP3) formation was inhibited by 1 microM-4 beta-phorbol 12,13-dibutyrate (PDBu) in rat parotid acinar cells. The inhibitory effect of PDBu was reversed by the protein kinase C inhibitors H-7 or K252a. Substance P also elicits a persistent desensitization of subsequent substance P-stimulated InsP3 formation. However, this desensitization was not inhibited by H-7. In addition, H-7 had no effect on the time course of substance P-induced InsP3 formation. These results suggest that, although activation of protein kinase C by phorbol esters can inhibit the substance P receptor-linked phospholipase C pathway, this mechanism apparently plays little, if any, role in regulating this system after activation by substance P.


Sign in / Sign up

Export Citation Format

Share Document