Involvement of protein kinase C in gamma-aminobutyric acid release from Xenopus oocytes injected with rat brain mRNA.
Involvement of protein kinase C (PKC) in the release of gamma-aminobutyric acid (GABA) was examined in Xenopus laevis oocytes injected with mRNA from rat cerebellum, as compared with findings in slices of rat cerebellum. The mRNA-injected oocytes preloaded with [3H]GABA showed spontaneous release of [3H]GABA, approximately 0.5% of GABA content per 1 min. Stimulation with either Ca2+ ionophore (A23187) or a high K+ concentration increased the release of [3H]GABA from slices of rat deep cerebellar nucleus and mRNA-injected oocytes but not from noninjected and water-injected oocytes. 12-O-Tetradecanoylphorbol 13-acetate (10-300 nM) but not 4alpha-phorbol 12,13-didecanoate (300 nM) potentiated the A23187-stimulated release of [3H]GABA from slices and from mRNA-injected oocytes, in a concentration-dependent manner. Thus, machinery associated with release processes of GABA can be expressed in oocytes by injecting rat cerebellar mRNA, and PKC participates in GABA release from the functionally expressed GABAergic nerve terminals.
Kan
S
S
Department of Pharmacology II, Nagasaki University School of Medicine, Japan.
Mameya
S
S
Kataoka
Y
Y
Kaibara
M
M
Yamashita
K
K
Taniyama
K
K
D000818:Animals; D001921:Brain / Q000502:physiology*; D000001:Calcimycin / Q000494:pharmacology; D008845:Microinjections; D009865:Oocytes; D011189:Potassium Chloride / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D012333:RNA, Messenger / Q000502:physiology; D051381:Rats; D014982:Xenopus laevis; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D012333:RNA, Messenger; D000001:Calcimycin; D005680:gamma-Aminobutyric Acid; D011189:Potassium Chloride; D011493:Protein Kinase C