Effects of Shilajit on the development of tolerance to morphine in mice

Effects of concomitant administration of Processed Shilajit (PS, 0.1 and 1 mg/kg, i.p.), in Swiss mice were evaluated on the development of tolerance to morphine induced analgesia in the hot plate test. Chronic administration of morphine (10 mg/kg, i.p,, b.i.d.) to mice over a duration of 10 days re sulted in the development of tolerance to the analgesic effect of morphine. Concomitant administration of PS with morphine, from day 6 to day 10, resu lted in a significant inhibition of the development of tolerance to morphin e (10 mg/kg, i.p.) induced analgesia. Processed Shilajit per se, in the dos es used, did not elicit any significant analgesia in mice; nor did the chro nic concomitant administration of Processed Shilajit alter the morphine-ind uced analgesia, These findings with Processed Shilajit indicate its potenti al as a prospective modifier of analgesic tolerance to morphine. Copyright (C) 2001 John Wiley & Sons, Ltd.