Immunohistochemistry Localization And Immunoregulation Of Met-Enkephalin In Octopus Ocellatus Gray

For the cephalopod has no special immunity ability, the cephalopod maily depends on phagocytosis of immunocytes, hydrolytic enzymes, oxidant enzymes and oxygen reactive species to kill phagocyted organisms. Moreover, there are enkephalin, interleukin-1 and tumor necrosis factor participating in the regulation and improvement of the immune processes. Met-enkephalin (Met-ENK) is one of the opioid neuropeptide. By studying the functions of opioid peptide and their receptors, it was found that opioid peptide could regulate cardiovascular system, digestive system, respiratory to some extent. The research on immune regulation of Met-ENK to Octopus ocellatus wasn't reported before. We studied the distribution of Met-ENK, delta receptor, mu receptor in the organs of Octopus ocellatus with immunohistochemical technique, and studied the impact of Met-ENK to some of the immune factors in the hemolymph with biochemical methods, give help with cephalopod immunology.Using the immunohistochemical technique, nerve cell bodies and fibres immunoreactive to the anti-Met-enkephalin sera were observed in the cerebral ganglia, pedal ganglia, visceral ganglia, inspect ganglia and coat ganglia of Octopus ocellatus. Met-ENK immunoreactivity was also localized in the mouth, esophagus, craw, stomach, stomachic caecus, the epithelium of the intestines, rectum, sialoid gland, liver, branchia, branchia gland, ventricle, branchial heart, kidneys, ovary, fallopian tube, back of mantle, abdomen of mantle, wrist, membrane of wrist, funnel, and immunocytes of Octopus ocellatus. By the same method, delta receptor was detected on the cerebral ganglia, pedal ganglia, visceral ganglia, coat ganglia and in the mouth, esophagus, craw, stomach, stomachic caecus, the epithelium of the intestines, sialoid gland, branchia, branchia gland, ventricle, branchial heart, kidneys, ovary, fallopian tube, back of mantle, abdomen of mantle, wrist, membrane of wrist, funnel and immunocytes of Octopus ocellatus. Mu receptor was localized in the esophagus, stomach, back of mantle, membrane of wrist of Octopus ocellatus. Since Met-ENK and opioid receptors are very abundant in many tissues of Octopus ocellatus, met-Enkephalin was likely to accommodate nerve, assimilation, respiration, exudation, procreate, incretion, sense, movement and immunity of Octopus ocellatus Gray. The met-Enkephalin which was excreted by nervous system maybe transport by nervous fibre, haemal circulation. And the different density of met-Enkephalin, delta receptor, mu receptor may be referable to different function of organ.To study the effects of Met-ENK on immunoregulation of Octopus ocellatus, the content of hydrogen peroxide(H2O2), glutathione (GSH), nitric oxide ( NO) and four kinds of enzymes participating in the immune defence in the haemolymph of Octopus ocellatus were assayed after 1, 5, 25μg/ml Met-ENK were added into the haemolymph. The results were as follows. (1) When the concentration of Met-ENK was between 1.00μg/ml and 5.00μg/ml, the methionine aminopeptidases (MetAP) activities in the serum of Octopus ocellatus were restrained faintishly; when the concentration of Met-ENK was 25.00μg/ml, the methionine aminopeptidases (MetAP) activities in the serum of Octopus ocellatus were restrained strongly. The MetAP activities in the blood cell were enhanced strongly with increasing concentration of the Met-ENK. (2) When the concentration of Met-ENK was between 1.00μg/ml and 25.00μg/ml, the catalase (CAT) activities in the blood cell were enhanced; the catalase (CAT) activities in the serum were restrained. The levels of H2O2 in the serum of Octopus ocellatus were decreased; when the concentration of Met-ENK was between 5.00μg/ml and 25.00μg/ml, the levels of H2O2 in the blood cell of Octopus ocellatus were increased. (3) The myeloperoxidase (MPO) activities which don't depend on halogen in blood cell of Octopus ocellatus were enhanced greatly at the low concentration of the Met-ENK and enhanced faintishly at the high concentration of the Met-ENK. The MPO activities which don't depend on halogen in the serum were restrained faintishly after Met-ENK was added. (4) The content of glutathione (GSH) was decreased after Met-ENK was added. (5) Theα-Naphthy Acetate Esterase (ANAE) activities were restrained greatly after Met-ENK was added. Overall, the data strongly suggests an involvement of Met-ENK in the regulation and improvement of the immune processes of Octopus ocellatus.