Immunocytochemical demonstration of the co-storage of noradrenaline with Met-enkephalin-Arg6-Phe7 and Met-enkephalin-Arg6-Gly7-Leu8 in the carotid body chief cells of the dog.
Cellular and ultrastructural localization of catecholamines in the dog carotid body was investigated by peroxidase-antiperoxidase method for light microscopy and by protein A-colloidal gold technique for electron microscopy, and compared with that of preproenkephalin A-related opioid peptides, i.e., Met-enkephalin-Arg6-Phe7 (Met-Enk-Arg-Phe) and Met-enkephalin-Arg6-Gly7-Leu8 (Met-Enk-Arg-Gly-Leu). Immunocytochemistry at the light microscopic level using consecutive semi-thin sections of Araldite-embedded tissue showed that some 30% of the chief cells contained immunoreactive noradrenaline together with Met-Enk-Arg-Phe and Met-Enk-Arg-Gly-Leu. A considerable number of chief cells exhibited immunoreactivities representing one or two of these three kinds of substances. A few chief cells showed none of the specific immunoreactivities. Immunoreactive adrenaline was not demonstrated in any cells of the dog carotid body. At the electron microscopic level, co-existence of noradrenaline with Met-Enk-Arg-Phe or Met-Enk-Arg-Gly-Leu in the same secretory granules was shown using the double labeling protein A-colloidal gold technique. Possible interactions of catecholamines and opioid peptides deserve consideration for the understanding of the chief cell's role in the carotid body chemoreceptor.
D000313:Adrenal Medulla / Q000032:analysis; D000818:Animals; D002344:Carotid Body / Q000032:analysis* / Q000166:cytology / Q000648:ultrastructure; D002395:Catecholamines / Q000032:analysis*; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D004285:Dogs; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000032:analysis; D004837:Epinephrine / Q000032:analysis; D005260:Female; D006651:Histocytochemistry; D007124:Immunoenzyme Techniques; D008297:Male; D009638:Norepinephrine / Q000032:analysis; D013194:Staining and Labeling
D002395:Catecholamines; D004744:Enkephalin, Methionine; C027511:enkephalin-Met, Arg(6)-Phe(7)-; C033453:enkephalin-Met, Arg(6)-Gly(7)-Leu(8)-; D009638:Norepinephrine; D004837:Epinephrine