The effect of CCK receptor agonists and antagonists in sciatic nerve-ligated mice

The effects of caerulin, a CCK receptor agonist, and proglumide, a receptor antagonist, on hyperalgesia induced by sciatic nerve ligation, was studied in mice. Tolerance to the morphine response was obtained 3,7, 14,21 and 28 days after unilateral sciatic nerve ligation. Maximum hyperalgesia was found 14 days after nerve ligation. Caerulin increased morphine antinociception in nerve-ligated animals. The drug also induced antinociception in intact animals. Proglumide also induced antinociception in nerve-ligated mice. The antagonist increased the morphine response but did not alter the effect of caerulin. We conclude that the CCK receptor mechanism may have a role in hyperalgesia induced by nerve ligation