A role for protein kinase C in the electrically evoked release of [3H] gamma-aminobutyric acid in rabbit caudate nucleus.
A possible participation of protein kinase C (PKC) in depolarization-induced release of gamma-aminobutyric acid (GABA) in rabbit caudate nucleus was examined by means of phorbol esters and staurosporine. Slices of caudate nucleus were loaded with [3H]GABA, then superfused and stimulated electrically (3 ms, 5 Hz, 24 mA, 5 V/cm) for 2 min. Aminooxyacetic acid and the uptake inhibitor nipecotic acid were present throughout. The PKC activator 4 beta-phorbol 12,13-dibutyrate (4 beta-PDB) markedly enhanced the evoked [3H]GABA release. In contrast, its biologically inactive isomer, 4 alpha-PDB, did not facilitate transmitter release. Staurosporine, an inhibitor of PKC, diminished [3H]GABA release and counteracted the effects caused by 4 beta-PDB. The above results suggest a participation of PKC in depolarization-induced GABA release in rabbit caudate nucleus. The mechanism underlying the modulation of GABA release by PKC seems to be independent of presynaptic GABA, dopamine and 5-hydroxytryptamine receptors.
Bartmann
P
P
Pharmakologisches Institut der Universität, Freiburg, Federal Republic of Germany.
Jackisch
R
R
Hertting
G
G
Allgaier
C
C
D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D002421:Caudate Nucleus / Q000201:enzymology / Q000378:metabolism* / Q000502:physiology; D004558:Electric Stimulation; D066298:In Vitro Techniques; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011817:Rabbits; D019311:Staurosporine; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D000470:Alkaloids; D015240:Phorbol 12,13-Dibutyrate; D005680:gamma-Aminobutyric Acid; D011493:Protein Kinase C; D019311:Staurosporine