Dynorphin converting enzyme in the rat spinal cord. Decreased activities during acute phase of adjuvant induced arthritis. |
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Authors: | J Silberring T Sakurada F Nyberg |
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Affiliation: | Department of Pharmacology, University of Uppsala, Sweden. |
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Abstract: | This paper describes a study on a dynorphin converting enzyme in spinal cord homogenates from rats with experimental arthritis after adjuvant injection into one hindpaw. The enzyme resembles a neutral cysteine endopeptidase which cleaves the opioid peptide dynorphin B and generates its N-terminal fragment, Leu-enkephalin-Arg6 with opioid activity. It exhibits considerably lower activity against dynorphin A and alpha-neoendorphin, the two other prodynorphin derived peptides. The enzyme showed significantly higher activity in the dorsal part than in the ventral part of the spinal cord. A significant decrease in enzyme activity was observed in the dorsal spinal cord during inflammation as compared to vehicle-injected controls. This decrease paralleled a decrease in the tissue level of Leu-enkephalin-Arg6. These data thus indicate that adjuvant-induced arthritis may generate an important change in a converting enzyme acting on peptide structures, which may be involved in pain modulation. Therefore, a functional role of the present enzyme in the regulation of pain-related peptides is suggested. |
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