Role of protein kinase C in the vesicular release of acetylcholine and norepinephrine from enteric neurons of the guinea pig small intestine.
The involvement of protein kinase C in the release of [3H]acetylcholine (ACh) and [3H]norepinephrine (NE) was studied in strips of guinea pig small intestine. 12-O-tetradecanoyl phorbol 13-acetate (TPA), but not 4 alpha-phorbol-12,13-didecanoate (4 alpha-PDD) potentiated the A23187-evoked release of [3H]ACh and [3H]NE from the strips of small intestine preloaded with [3H]choline and [3H]NE, and the potentiating effect of TPA was inhibited by polymyxin B. High K+-evoked releases of [3H]ACh and [3H]NE in the presence of tetrodotoxin were also potentiated by TPA. These TPA-induced potentiations of the evoked release were greater at a low concentration of external Ca2+ (0.5 mM) than at a high concentration (2 mM). Ouabain induced the release of these neurotransmitters both in the absence and presence of the low concentration of external Ca2+. The ouabain-evoked release was not altered by TPA. These results indicate that the activation of protein kinase C potentiates the vesicular release of ACh and NE at low Ca2+ concentration from the nerve terminals of enteric neurons in the guinea pig small intestine.
Hashimoto
S
S
Department of Pharmacology, Kobe University School of Medicine, Japan.
Shuntoh
H
H
Taniyama
K
K
Tanaka
C
C
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000201:enzymology / Q000294:innervation / Q000378:metabolism*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000001:Calcimycin; D010042:Ouabain; D011493:Protein Kinase C; D000109:Acetylcholine; D013755:Tetradecanoylphorbol Acetate; D011188:Potassium; D009638:Norepinephrine