Effects of valsartan on morphine tolerance and dependence in rats.

Background And Purpose: Opiates are traditionally used for the treatment of pain. Chronic consumption of opiates such as morphine (MOR) induces tolerance and dependence. This study aimed to investigate the effects of valsartan (VAL), as an angiotensin II receptor blocker, on the induction and expression of MOR analgesic tolerance and physical dependence in rats.

Sumatriptan effects on morphine-induced antinociceptive tolerance and physical dependence: The role of nitric oxide.

Sumatriptan, a 5HT (5-hydroxytryptamine) receptor agonist, showed neuroprotection in different studies. The aim of the present study was to investigate the effect of sumatriptan on morphine-induced antinociceptive tolerance and physical dependence. We also investigated the possible role of nitric oxide (NO) on sumatriptan effects.