Effect of amitriptyline on analgesia induced by acupuncture and inescapable painful electrodermal stimulation in the rat

: The effect of amitriptyline (1.5 and 3 mg/kg intraperitoneally once a day for 1, 3, 5 days) on the latencies (L) of hot plate (HP) and tail flick (TF) at rest, after acupuncture (A) of bilateral Ho-ku and after inescapable foot-shock (IFS--1.0 mA, 50 Hz, 5 min) was studied in experiments on rats. It was shown that amitriptyline in the above doses, used in different periods of time, failed to effect L of HP and TF at rest. However, after A an increase of the analgesic effect was observed in the rats treated with 3 mg/kg of amitriptyline for 3 days. In the experiment with IFS an increase of the effect was pronounced in TF test 24 hours following administration of 1.5 and 3.0 mg/kg of amitriptyline.