Effects of NSAIDs and paracetamol (acetaminophen) on protein kinase C epsilon translocation and on substance P synthesis and release in cultured sensory neurons

Abstract

Celecoxib, diclofenac, ibuprofen, and nimesulide are nonsteroidal anti-inflammatory drugs (NSAIDs) very commonly used for the treatment of moderate to mild pain, together with paracetamol (acetaminophen), a very widely used analgesic with a lesser anti-inflammatory effect. In the study reported here, we tested the efficacy of celecoxib, diclofenac, and ibuprofen on preprotachykinin mRNA synthesis, substance P (SP) release, prostaglandin E2 (PGE2) release, and protein kinase C epsilon (PKCɛ) translocation in rat cultured sensory neurons from dorsal root ganglia (DRGs). The efficacy of these NSAIDs was compared with the efficacy of paracetamol and nimesulide in in vitro models of hyperalgesia (investigated previously). While nimesulide and paracetamol, as in previous experiments, decreased the percentage of cultured DRG neurons showing translocation of PKCɛ caused by 100 nM thrombin or 1 μM bradykinin in a dose-dependent manner, the other NSAIDs tested did not have a significant effect. The amount of SP released by peptidergic neurons and the expression level of preprotachykinin mRNA were assessed in basal conditions and after 70 minutes or 36 hours of stimulation with an inflammatory soup (IS) containing potassium chloride, thrombin, bradykinin, and endothelin-1. The release of SP at 70 minutes was inhibited only by nimesulide, while celecoxib and diclofenac were effective at 36 hours. The mRNA basal level of the SP precursor preprotachykinin expressed in DRG neurons was reduced only by nimesulide, while the increased levels expressed during treatment with the IS were significantly reduced by all drugs tested, with the exception of ibuprofen. All drugs were able to decrease basal and IS-stimulated PGE2 release. Our study demonstrates novel mechanisms of action of commonly used NSAIDS.

Gabapentin Inhibits Protein Kinase C Epsilon Translocation in Cultured Sensory Neurons with Additive Effects When Coapplied with Paracetamol (Acetaminophen)

“…Finally, the secondary antibody was rinsed off with PBS and cells were analyzed using a confocal microscope (Leica SP2, Leica Microsystems, Milan, Italy). Activation of PKC ε following activation of bradykinin or prokineticin receptors (PKRs) resulted in translocation from the cytoplasm to the neuronal cell membrane, as shown several times before [19, 20]. Translocation was quantified by determining fluorescence intensity along a line positioned across the cell in order to avoid the nucleus (for details, see Cesare et al [21]) using semiautomated proprietary software which significantly improved efficiency of data analysis.…”

Nimesulide in Treatment of Acute and Chronic Pain in Clinical Practice

“…На культуре нейронов задних спинальных ганглиев, дающих начало чувствительному корешку, было продемонстриро-вано, что только нимесулид обладает способностью пода-влять концентрацию субстанции Р в течение 70 мин, в то время как другие препараты (целекоксиб, диклофенак) -только через 36 ч [31].…”

Osteoarthritis of the hand II: chemistry, pharmacokinetics and pharmacodynamics of naproxen, and clinical outcome studies

“…Na v 1.7 and Ca v 2.1) that are affected by NSAIDs . There are indications that the effects of NSAIDs on release of substance P and PGE 2 , and protein kinase C‐ε translocation varies with individual drugs . Gene expression studies of L4 and L5 dorsal root ganglia from acutely inflamed arthritic rats have shown that naproxen or the α‐adrenergic antagonist, phenoxybenzamine, both reduced allodynia and nociceptive behaviour coincident with changes in the expression of inflammatory radiator proteins described collectively in a Connectivity Map.…”

“…[31] There are indications that the effects of NSAIDs on release of substance P and PGE2, and protein kinase C-ε translocation varies with individual drugs. [32] Gene expression studies of L4 and L5 dorsal root ganglia from acutely inflamed arthritic rats have shown that naproxen or the α-adrenergic antagonist, phenoxybenzamine, both reduced allodynia and nociceptive behaviour coincident with changes in the expression of inflammatory radiator proteins described collectively in a Connectivity Map. While there are no data on the effects of the drugs on expression of the inflammatory mediator proteins, the results suggest that inhibition of α-adrenergic functions control inflammation in a way similar to that of naproxen.…”