Carbachol and oxytocin stimulate the generation of inositol phosphates in the guinea pig myometrium.
In the guinea pig myometrium prelabelled with myo-[2-3H]inositol, carbachol and oxytocin enhanced a concentration-dependent and rapid release of IP3 which preceded that of IP2 and IP1. The specific receptor-mediated phospholipase C activation degrading PIP2 to IP3 did not require the presence of extracellular Ca2+. The ionophore A23187 as well as K+ depolarization failed to increase inositol phosphate accumulation. It is proposed that IP3 could have a role in the contraction of uterine smooth muscle elicited by the activation of muscarinic as well as of oxytocin receptors.
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology*; D002712:Chlorides / Q000494:pharmacology; D005260:Female; D006168:Guinea Pigs; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000378:metabolism*; D007700:Kinetics; D008094:Lithium / Q000494:pharmacology; D018021:Lithium Chloride; D009215:Myometrium / Q000187:drug effects / Q000378:metabolism*; D010121:Oxytocin / Q000494:pharmacology*; D011945:Receptors, Angiotensin / Q000502:physiology; D011976:Receptors, Muscarinic / Q000502:physiology; D018045:Receptors, Oxytocin; D013403:Sugar Phosphates / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism
D002712:Chlorides; D007295:Inositol Phosphates; D011945:Receptors, Angiotensin; D011976:Receptors, Muscarinic; D018045:Receptors, Oxytocin; D013403:Sugar Phosphates; D000001:Calcimycin; C044259:inositol 1,4-bis(phosphate); D010121:Oxytocin; D015544:Inositol 1,4,5-Trisphosphate; D002217:Carbachol; D008094:Lithium; D010738:Type C Phospholipases; D018021:Lithium Chloride; D002118:Calcium