Study of antinociceptive effect of paroxetine and elucidation of its mechanism of action in acute pain in albino rats

Abstract

Pain is the most common reason patients seek medical care. Increased level of monoamines (serotonin and norepinephrine) in synaptic clefts lead to changes in pain threshold and induce antinociception. The study was carried out to evaluate anti- nociceptive effect of paroxetine in albino rats and to probe into its possible mechanism of action. Albino rats of either sex of average weight 100-200gms were used. The drugs used were paroxetine 5mg/Kg, pethidine 5mg/Kg(active control), naloxone 5mg/Kg, ondansetron 0.1mg/Kg and normal saline 1ml/Kg. Antinociceptive effect tested by using thermal method i.e. tail flick response. Statistical analyses indicate significant difference between value of control when compared with paroxetine i.e., paroxetine shows antinociceptive effect. The effects of paroxetine were comparable to that of pethidine. Naloxone, an opioid receptor antagonist and Ondansetron, a 5HT-3 receptor antagonist when combined with paroxetine blocked its antinociceptive action. This finding suggests and involvement of serotonergic mechanisms (5-HT3 subtype), and the opioidergic system