Evaluation of Antidepressant and Antinociceptive Activity of Escitalopram

Escitalopram, the S - (+) -enantiomer of citalopram, is a selective serotonin reuptake inhibitor with potent effects in animal models predictive of antidepressant and anxiolytic activities. In this present study, antidepressant activity and antinociceptive effects of escitalopram (ESC, 40 mg/kg) have been studied in forced swim test, tail suspension test, hot plate test, acetic acid writhing and formalin tests in rodents. A significant (P< 0.05) antidepressant-like effect was shown at dose of 40 mg/kg, which was due to reduction in the immobility period. ESC 40 mg/kg also presented an analgesic effect, in our studies. ESC 40mg/kg produced a significant (P<0.05) % increase in latency at time intervals 60, 90 and 120 min in thermal pain studies in mice. It also significantly inhibited acetic acid induced abdominal constrictions, with the maximal effect (55.95 % protection) at 40 mg/kg. In formalin induced paw licking pain model, ESC exhibited more pronounced effect in the inflammatory phase than the neurogenic phase (maximal effect was 54.17±3.89 s and 87.83±1.64s, respectively, at 40 mg/kg, i.p.). The present study showed that ESC has equal efficacy in comorbid pain and depression-like behaviour mediated through serotonergic system.