title: Effects of GABA and L-glutamic acid on the potassium-evoked in vitro release of substance P- and neurokinin A-like immunoreactivities are different in the rat striatum and substantia nigra.
abstract: Slices of the rat substantia nigra and striatum were superfused in vitro to measure release of tachykinins (TKs). Potassium (30 and 60 mM) infusion caused a 3- to 10-fold outflow of both substance P-like immunoreactivity (SP-LI) and neurokinin A-like immunoreactivity (NKA-LI) in the substantia nigra as well as in the striatum as measured by radioimmunoassay. The potassium-evoked release of SP-LI and NKA-LI was significantly, but not completely (by 25-70%) inhibited by simultaneous perfusion with L-glutamic acid (50 microM) and gamma-aminobutyric acid (GABA, 50 microM) in the substantia nigra. No significant inhibition was, however, observed in the striatum. The present data indicate a differential regulation of tachykinins in the striatum and substantia nigra by L-glutamic acid and GABA. The presynaptic regulation of TK release may therefore differ in the dendritic and terminal region of the striatonigral pathway.
authors.affiliation: Department of Psychiatry, University Hospital Innsbruck, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Humpel
authors.forename: A
authors.initials: A
authors.lastname: Saria
mesh_terms: D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D005071:Evoked Potentials / Q000187:drug effects*; D005260:Female; D005971:Glutamates / Q000494:pharmacology*; D018698:Glutamic Acid; D066298:In Vitro Techniques; D015288:Neurokinin A / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013373:Substance P / Q000378:metabolism*; D013378:Substantia Nigra / Q000187:drug effects / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
chemical_list: D005971:Glutamates; D013373:Substance P; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D011189:Potassium Chloride; D015288:Neurokinin A; D011188:Potassium