Authors studied the regulatory mechanism of protein kinase C on the action of acetylcholine in rabbit carotid artery. The arterial rings were myographied isometrically in an isolated organ bath. In this study, acetylcholine relaxed phenylephrine-induced contraction of rabbit carotid artery in the presence of endothelium. In the pretreatment of methylene blue or nitro-L-arginine, the action of acetylchioline was reduced. Pretreatment of phorbol 12-myristate 13-acetate(PMA) attenuated the action of acetylcholine, but PMA did not attenuated it in the presence of staurosporine, suggesting that protein kinase C suppressed the action of acetylcholine. The potency of phorbol ester on the action of acetylcholine was PMA>phorbol 12, 13-dibutyrate(PDBu)>phorbol 12,13-diacetate(PDA), but the direct effect of phorbol on the contraction of arterial rings was PDBu>PMA>PDA. This implied that protein kinase C involved in the contraction of smooth muscle and the attenuation of the action of acetylcholine were different. PMA did not affect on A23187- and sodium nitroprusside-induced vasorelaxation. Acetylcholine increased tissue cGMP contents, which was reduced by PMA. These results suggest that in rabbit carotid artery protein kinase C reduce acetylcholine-stimuated endothelium derived relaxing factor(EDRF) release by affecting membrane receptor, and do not affect on the function of EDRF and cGMP production in the smooth muscle.
Acetylcholine* ; Baths ; Carotid Arteries* ; Endothelium ; Membranes ; Methylene Blue ; Muscle, Smooth ; Protein Kinase C ; Sodium ; Staurosporine ; Vasodilation

A large tumor located at right temporoparietal lobe was found in 25-years-old female. The brain CT scan and MR imaging revealed a large multi-lobulated mass which was composed of solid and cystic portions involving right temporoparietal lobe. Preoperative routine laboratory check showed microcytic hypochromic anemia and monoclonal gammopathy with bate-gamma bridging. The mass was removed totally by operation and histologic diagnosis resulted in chordoid meningioma surrounded by massive polyclonal lymphoplasmacellular infiltrates. After the mass was removed, the blood picture of the patient normalized and the patient discharged with neurologically free stage. We report this case with relative literatures.
Anemia, Hypochromic ; Brain ; Diagnosis ; Female ; Humans ; Magnetic Resonance Imaging ; Meningioma* ; Paraproteinemias ; Tomography, X-Ray Computed