Effects Of Leucine-enkephalin On The Immunoregulation Of Chlamys Farreri

The mollusk's nervous system is simple and sparse. The mollusk hasn't specialneuroendocrine apparatus and the mollusk's nervous system has the function of secretion.Being no special immune ability, the mollusk mainly depends on phagocytosis ofimmunocytes, hydrolytic enzymes, oxidant enzymes and oxygen reactive species to killphagocyted organisms. Moreover, there are enkephalin, interleukin-1, interleukin-2,interleukin-6 and tumor necrosis factor participating in the regulation and improvement of theimmune processes.Using immunohistochemical technique, we observed nerve cell bodies and fibres wereimmunoreactive to anti-Leu-enkephalin sera in the cerebral ganglia, pedal ganglia, visceralganglia and osphradium ganglia of C hlamys farreri. Leu-enkephaline(L-ENK)immunoreactivity was also localized in the epithelium of the intestines, rectum, digestivediverticula, labial palps, mouth labia, kidneys and immunocytes ofChlamys farreri. By thesame method, delta-, mu-, and kappa receptors were detected on cerebral ganglia, pedalganglia, visceral ganglia and osphradium ganglia ofChlamys farreri. These receptors werealso localized in the epithelium of the intestines, rectum, stomach, digestive diverticula, labialpalps, mouth labia, kidneys, mantle, gill, gonad and immunocytes ofChlamys farreri, too.Since L-ENK and opioid receptors are very abundant in lots of tissues ofChlamys farreri,Leu-enkephalin may engage in receptor-mediated immunity, digestion, breath and excretionactivities.To study the effects of L-ENK on immunoregulation of Chlamys farreri, the content ofnitric oxide ( NO) , hydrogen peroxide(H2O2), glutathione (GSH) and five kinds of enzymesparticipating in the immune defence system in the haemolymph of Chlamys farreri wereassayed after 1, 5, 50 μg/ml L-ENK were added into the haemolymph. The phagocytosis,encapsulation, conglomeration and adhesive abilities of Chlamys farreri haemocytes wereinvestigated after 1, 5, 50 μg/ml L-ENK were added into the haemolymph, too. The results areas follows. (1) The catalase (CAT) activities in the serum and blood cell were enhanced withincreasing concentration of the L-ENK and the levels of H2O2 in the blood cell of Chlamysfarreri were decreased significantly related in part to increased CAT activities. (2) Theconstitutive NOS (cNOS) and inducible NOS (iNOS) activities changed with increasingconcentrion of the L-ENK. Too high or too low concentration of the L-ENK couldn't beststimulate the nitric oxide synthase (NOS) activities. Low concentration of the L-ENKincreased plasma levels of NO significantly related in part to increased NOS activities, whileit didn't affect the levels of NO in the blood cell. (3) The myeloperoxidase (MPO) activities inblood cell of Chlamys farreri were decreased at the low concentration of L-ENK andenhanced at the high concentration of the L-ENK. The MPO activities not depending onhalogen in the serum were enhanced after different concentrations of L-ENK were added. (4)The content of glutathione (GSH) was enhanced after different concentrations of L-ENK wereadded. (5) The α-Naphthy Acetate Esterase (ANAE) activities were enhanced after differentconcentrations of L-ENK were added. (6) The phagocytosis ability of Chlamys farrerihaemocytes were enhanced with increasing concentration of the L-ENK. But theencapsulation activities of Chlamys farreri haemocytes changed with increasing concentrationof the L-ENK. At the concentration of 50 μg/ml, L-ENK stimulated the encapsulationactivities, while at the concentration of 5 μg/ml, L-ENK decreased the encapsulation activities.(7) At the concentration of 1 μg/ml, L-ENK decreased the conglomeration activities ofhaemocytes, but high concentrations of L-ENK have no effect on the conglomerationactivities of haemocytes. At the concentration of 1 μg/ml, L-ENK has no effect on theadhesive activities of haemocytes, and high concentrations of L-ENK decreased the adhesiveactivities of haemocytes.Overall, by binding with opioid receptors, L-ENK can participate in the regulation andimprovement of the immune processes of Chlamys farreri.