Somatostatin precursor in the rat striatum: changes after local injection of kainic acid.
The molecular forms of somatostatin contained in the rat striatum were separated by size-exclusion HPLC. Three major peaks of somatostatin-like immunoreactivity (SLI) were resolved. Two peaks cochromatographed with synthetic somatostatin-14 (SS-14) and somatostatin-28 (SS-28), respectively. One peak exhibited a higher molecular weight (about 10,000) and may contain a proform of somatostatin. Local injection of the neurotoxin kainic acid (1 microgram) into the left striatum resulted in a persistent decrease (65-85%) of all three forms of somatostatin. In the contralateral--not injected--striatum a decrease of SLI was also observed which was maximal (45%) after 2 days and was largely abolished after 7 days. This decrease of SLI in the contralateral striatum, however, was due mainly to a decrease of SS-14 and SS-28 but not of the putative proform. Our data suggest that kainic acid causes a destruction of somatostatin-containing perikarya in the injected striatum, whereas in the contralateral striatum increased release with subsequent inactivation of SS-14 and SS-28 takes place. The putative somatostatin proform may serve as neurochemical marker for somatostatin-containing perikarya in the striatum.
Sperk
G
G
Widmann
R
R
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D007608:Kainic Acid / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D011498:Protein Precursors / Q000302:isolation & purification / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000302:isolation & purification / Q000378:metabolism*; D053561:Somatostatin-28
D011498:Protein Precursors; D013004:Somatostatin; D053561:Somatostatin-28; D007608:Kainic Acid