Mn(2+)-induced transient contraction of the longitudinal muscle of guinea-pig stomach through prostaglandin synthesis.
1. A low concentration of Mn2+ (less than 0.3 mM) transiently enhanced a contractile force (Mn(2+)-induced TC) of the longitudinal muscles of the guinea-pig stomach. 2. The Mn(2+)-induced transient contraction (TC) was not blocked by TTX (10(-7) M) or atropine (10(-6) M), nor by nifedipine (10(-6) M) or D-600 (10(-6) M), but was blocked by Ca2+ removal from the Krebs solution. 3. A preapplication of indomethacin (10(-7) M) completely inhibited an induction of the Mn(2+)-induced TC, but exogenous PGE2 (10(-7) M) was able to induce Mn(2+)-induced TC even with the presence of indomethacin (10(-7) M) and Mn2+ (0.1 mM) in the Krebs solution. 4. Quinacrine (10(-5) M), a phospholipase A2 inhibitor, partially inhibited the Mn(2+)-induced TC. 5. These results suggest that Mn(2+)-induced TC is probably mediated through cyclooxygenase and the subsequent generation of prostaglandin leading to the contraction.
Sakamoto
Y
Y
Department of Physiology, School of Medicine, Fukuoka University, Japan.
Inoue
M
M
Imanaga
I
I
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D008345:Manganese / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism* / Q000502:physiology; D009543:Nifedipine / Q000494:pharmacology; D010741:Phospholipases A / Q000037:antagonists & inhibitors; D054467:Phospholipases A2; D011453:Prostaglandins / Q000096:biosynthesis*; D011796:Quinacrine / Q000494:pharmacology; D013270:Stomach / Q000187:drug effects / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology
D002121:Calcium Channel Blockers; D016861:Cyclooxygenase Inhibitors; D004791:Enzyme Inhibitors; D018727:Muscarinic Antagonists; D011453:Prostaglandins; D008345:Manganese; D013779:Tetrodotoxin; D001285:Atropine; D010741:Phospholipases A; D054467:Phospholipases A2; D011796:Quinacrine; D009543:Nifedipine; D002118:Calcium; D007213:Indomethacin