Abstract
To examine the processing of products of the dynorphin gene in the central nervous system, immunoreactive (ir) dynorphin (Dyn) A, Dyn B, Dyn A-(1-8), alpha- and beta-neo-endorphin (alpha- and beta-Neo) in rat brain and spinal cord were measured, using specific antisera after gel filtration and high-performance liquid chromatography (HPLC). Three peaks of Mr about 8, 4, and 2 kDa for ir-Dyn A and ir-Dyn B, and one peak of Mr less than 2 kDa for ir-Dyn A-(1-8), ir-alpha-, and ir-beta- Neo were found both in the brain and in the spinal cord. The 8 kDa peak was recognized by Dyn A and Dyn B antisera and, after hydrolysis by proline-specific endopeptidase, by beta-Neo antiserum. The 8 kDa peak was recognized by a monoclonal antibody against the amino terminal sequence Tyr-Gly-Gly-Phe of all opioid peptides and by an antiserum directed toward the carboxyl terminus of Dyn B, indicating that it contains, from the amino terminal tyrosine of neo-endorphin to the carboxyl-terminal threonine of Dyn B, all 3 opioid peptide regions in the prodynorphin. By means of proline-specific endopeptidase hydrolysis, we also found a big dynorphin precursor (Mr approximately equal to 26 kDa) in both brain and spinal cord.