In vivo biosynthesis of 35S-substance P from [35S]methionine in the rat striatum and its transport to the substantia nigra.
Rats with a push-pull cannula implanted in the right striatum were used to study the biosynthesis of 35S-substance P (SP) from [35S]methionine and its transport to the ipsilateral substantia nigra. [35S]Methionine was delivered for 2, 3 or 5 h to the push-pull cannula. 35S-SP in striatal and nigral tissues was estimated after immunoadsorption and HPLC. Higher levels of 35S-SP in striatal homogenates were found after a 5-h labelling period. 35S-P biosynthesis was inhibited when cycloheximide was superfused together with [35S]methionine. The identity of 35S-SP was further checked by its conversion into 35S-SP sulphoxide. After a 5-h labelling period, 35S-SP was also recovered in the substantia nigra. This was not the case after hemisection of striato-nigral fibers. When rats were killed 15 or 24 h after the 5-h labelling period, 35S-SP levels in the substantia nigra were higher than those found just after 5-h labelling period, while the reverse was observed in the striatum.
D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D007839:Functional Laterality; D007700:Kinetics; D008297:Male; D008715:Methionine / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D011865:Radioisotope Dilution Technique; D051381:Rats; D013373:Substance P / Q000096:biosynthesis*; D013378:Substantia Nigra / Q000187:drug effects / Q000378:metabolism*; D013462:Sulfur Radioisotopes
D013462:Sulfur Radioisotopes; D013373:Substance P; D003513:Cycloheximide; D008715:Methionine