ANTAGONIZING EFFECT OF MORPHINE ON THE MOBILITY AND PHAGOCYTIC-ACTIVITY OF INVERTEBRATE IMMUNOCYTES

In the present study we have demonstrated that lipopolysaccharide (LPS ) acts as an activator in the immunocytes of molluscs Planorbarius cor neus, Mytilus edulis, and the insect Leucophaea maderae. This stimulat ory effect, demonstrated by cellular conformational changes, is concen tration- and time-dependent, and is antagonized by morphine. The inhib itory effect of morphine carl be counteracted by naloxone. Morphine in hibitory action on immunocyte activity is also demonstrated by a decre ase in the phagacytic activity. These data suggest that the downregula tion of morphine is not limited to vertebrates but is also present in invertebrates.