INTERACTION BETWEEN MORPHINE AND OPIOID-PEPTIDES AFTER SC ADMINISTRATION

It is possible that peripheral analgesic targets may enhance central analgesia. We present our preliminary results of selected opioid peptides on morphine (MOR) analgesia. Coinjection of dermorphin with MOR resulted in antinociceptive synergy, whereas morphiceptin coinjected with MOR yielded antinociceptive activity lower than MOR alone. At lower doses of MOR, DADLE strongly potentiates analgesia, but at higher doses of MOR, DADLE inhibits the antinociceptive effect of MOR.