7/28/2019 Iannitti Et Al., 2011 (Abstract Hamburg)

1/1

POSTER SESSIONS / European Journal of Pain Supplements 5 (2011) 15295 17

T107NEURITES OF PORCINE DRG NEURONS DIFFERENTIALLYSUPPORTED BY TROPHIC FACTORS AND CO-CULTURED WITHKERATINOCYTES

A. Klusch1, L. Ponce2, M. Ringkamp3, I. Schafer2, A. Holloschi2,M. Schmelz1, M. Hafner2, M. Petersen1 *. 1Anesthesiology,Universitatsmedizin Mannheim, 2Inst. Molecular Cell Biol., HochschuleMannheim, Mannheim, Germany; 3Neurosurgery, Johns HopkinsUniversity, Baltimore, MD, USA

Background and Aims: Our long term goal is to study the role ofnon-neuronal cells like keratinocytes in nerve terminal excitability.Methods: Outgrown neurites from dissociated porcine DRGneurons and porcine epidermal keratinocytes were used as amodel. Neurites were spatially separated from their somata ina compartmented chamber. Somata were cultured in the central

compartment. Outgrowth of neurites into the side compartmentswas supported by trophic factors NGF, GDNF or artemin. Oneside compartment contained medium without growth factors, theother one NGF, GDNF or artemin in different concentrations. Forco-culture, keratinocytes were seeded in the side compartments

in keratinocyte medium. Ca2+-imaging was performed to detectresponses in neurites and keratinocytes.Results: In mono-culture, with NGF in the central compartment,

processes grew only into the growth factor containing sidecompartment. With GDNF or artemin, there was neurite outgrowth

also into the control side. With NGF or GDNF in the lateralcompartment, about 60% of the neurites were capsaicin responsive.With GDNF in the central, but not in the lateral compartment,a clearly lower proportion was responsive. To investigate neurite/keratinocyte interaction, in a first step, we established a co-culture.

Neurites only were activated by a cross-compartment activationthrough KCl applied to the somata-containing compartment. Thisstimulation revealed a change in cytosolic calcium concentration inneurites and in adjacent keratinocytes.Conclusions: Using a compartmented chamber, neurites of

nociceptive neurons can be utilized to investigate informationprocessing alone or in co-culture with non-neuronal cells.Support: Land Baden-Wurttemberg and DFG, KFG 107.

Disclosure: None declared

T108PAIN SENSITIVITY AND PERIPHERAL INFLAMMATION AREINCREASED IN A RAT MODEL OF GENETIC OBESITY

T. Iannitti*, A. Graham, S. Dolan. Department of Biological andBiomedical Sciences, Glasgow Caledonian University, Glasgow, UK

Background and Aims: Obese individuals are more likely to be

affected by chronic pain conditions such as osteoarthritis, migraineand musculoskeletal conditions, and alterations in pain sensitivityhave been reported in obese rats, however the mechanismsunderlying these changes are not known. The aim of this studywas to investigate whether acute nociception and inflammatory

hyperalgesia are altered in a rodent model of genetic obesity.Methods: Hindpaw withdrawal latency to thermal stimulation,response thresholds to mechanical stimulation, and paw oedemawere assessed in male Zucker fatty rats (fa/fa) and theirlean littermates (fa/) (n= 69 per group) in the absence of

inflammation, then in response to intradermal hindpaw injectionof carrageenan (3%; 50 ml) or capsaicin (10mg; 50 ml) or hindpawincision.Results: There was no difference in acute thermal or mechanicalnociceptive responses between obese or lean animals. Following

carrageenan-induced inflammation, obese rats were significantlymore sensitive to mechanical and thermal stimulation of theinflamed paw, and displayed greater paw oedema compared tolean rats. No difference in capsaicin or paw incision induced mechanical and thermal hyperalgesia were observed between obese

and lean rats.

Conclusions: The increased hyperalgesia and peripheral inflamma-tion in obese rats fits well with the hypothesis that obesity is achronic low-grade inflammatory disorder, producing a state whereresponses to subsequent inflammatory challenge are potentiated.These alterations may underlie the increased susceptibilty of obeseindividuals to develop chronic inflammatory pain conditions, andsignal the need for more aggressive analgesic treatment regimes inthese individuals.

Disclosure: None declared

T109THE ROLE OF THE LYSOPHOSHATIDYLINOSITOLGPR55PATHWAY IN PERIPHERAL SENSITIZATION IN PAIN STATES

V. Gangadharan*, M. Kurejova, D. Skoricova, C. Njoo, D. Selvaraj,R. Kuner. Institute of Pharmacology, Heidelberg University, Heidelberg,Germany

Background and Aims: Recent studies have suggested thatthe orphan receptor GPR55 is activated by multiple differentcannabinoid ligands and also by L-a-lysophosphatidylinositol (LPI).GPR55 is reported to be expressed on sensory neurons andmice lacking GPR55 were shown to have reduced mechanicalhypersensitivity in experimental pain models, suggesting apronociceptive role of GPR55. LPI was found to be secreted in

large quantities from varieties of cancer tissue. These facts led usto speculate that LPI released from cancer cells could sensitizethe nociceptors and thereby lead to cancer-induced pain. The aimof the study was to investigate the role of LPI in cancer induced,mechanically evoked pain and its possible underlying mechanism.Methods: Mice were treated with intraplantar injections of eitherLPI or vehicle and mechanical sensitivity was measured usingVon Frey filaments. Inflammatory and demyelinating capacity ofLPI were studied using immunohistochemistry and toluidine bluestaining/electron microscopy. Dorsal root ganglion were culturedand used for western blot analysis.Results: We found that the dorsal root ganglion neurons weredirectly activated by LPI in vitro. We also found that intraplantarinjection of LPI lead to a mechanical hypersensitivity in a

dose dependent manner in wild type mice, without elicitingany inflammation or demyelination. LPI induced mechanicalhypersensitivity was significantly reduced in mice lacking GPR55.Conclusions: These results indicate a possible role of LPI/GPR55signaling pathway in cancer induced pain. Blocking of GPR55signaling with specific ligands might therefore serve as a potentialtherapeutic strategy to treat cancer induced pain.

Disclosure: None declared

T110CRITICAL RESIDUES OF THE INTRACELLULAR C-TERMINAL DO-MAIN OF ATP-GATED P2X3 RECEPTORS REGULATE FUNCTIONALDIFFERENCES BETWEEN HUMAN AND RAT RECEPTORS

M. Sundukova1 *, S. Vilotti1, N. Kavcic2, R. Abbate1, E. Fabbretti1,2,A. Nistri1. 1Neurobiology Sector and IIT Unit, SISSA, Trieste, Italy;

2University of Nova Gorica, Nova Gorica, Slovenia

Background and Aims: ATP-activated P2X3 receptors of sensoryneurons contribute to pain transduction and are involved inthe pathogenesis of chronic pain. The intracellular kinase Cskphosphorylates tyrosine 393 on the C-terminal of rat P2X3 receptor,and inhibits its function. Although rat and human P2X3 receptorsare rather homologous, in human P2X3 receptors tyrosine 393 isreplaced by phenylalanine. In this study we characterized pointmutations of key amino acid residues in the C-terminals of thehuman and rat receptors, to better understand the molecularrequirements for their function.Methods: P2X3 receptor-mediated currents were recorded withwhole cell patch clamping from HEK 293T cells transientlyexpressing human or rat wild-type P2X3 receptors, or selected

mutants in C-terminal domain. Constructs have been sequenced