Naltrindole sensitive delta 2 opioid receptor mediates invertebrate immunocyte activation.

Previous studies demonstrated the presence of a delta 2 opioid receptor on human and invertebrate immunocytes. The present study demonstrates that this new binding site regulates invertebrate immunocyte activation. In the present study we note that the select delta antagonist, naltrindole, at a low concentration (10(-11) M), can significantly inhibit DAMA induced activation. Interestingly, the general opioid and opiate antagonist, naloxone, is not effective at this low concentration, further suggesting that the delta 2 opioid receptor mediates opioid immunocyte activation. This conclusion is further supported by the fact that DPDPE and DADLE, known to influence delta 1 activity did not affect immunocyte activation at low concentrations.