[Nonsteroidal antiinflammatory drugs and nitric oxide]

Despite of belonging to different chemical groups all nonsteroidal antiinflammatory drugs (NSAIDs) exert on antiinflammatory, antypyretic and analgetic effects inhibiting prostaglandin synthesis, preciseley inhibiting first enzyme in arachidonic acid- cyclooxygenase. The aim of the study was to investigate the influence of NSAIDs on nitric oxide synthesis and releasing to bloodstream Acetylsalicic acid (ASA) and diclofenac as COX-1 and COX-2 inhibitors and nimesulide as selective COX-2 inhibitor were used in study.

An experiment was carried out on male Wistar rats administered intragastrically with acetylsalicylic acid in doses: 2.0 and 10.0 mg/kg of body weigh, diclofenac in doses: 1.0 and 5.0 mg/kg body weigh and nimesulide in doses: 2.5 and 12.5 mg/kg body weigh for three weeks. Results compared to control group which received water instead of achive drugs. Nitric oxide was determined by Nitric Oxide Non-Enzymatic Assay of Oxis International.

ASA and nimesulide use did not significantly influence NO plasma concentration. Diclofenac administration at the 1.0 and 5.0 mg/kg of body weigh was associated with increased NO concentration by 48.7% and 73.5% respectively.

NO concentration is not relevant to selective or non selective inhibition of COX by NSAIDs. ASA (a non selective NSAIDs) and nimesulide (sective NSAIDs) do not influence NO concentration, while diclofenac (non selective NSAIDs) causes an increase in NO blood concentration in rats.