Bradykinin induces a rapid release of inositol trisphosphate from a neuroblastoma hybrid cell line NCB-20 that is not antagonized by enkephalin.
In mouse neuroblastoma x Chinese hamster brain clonal cell line NCB-20, bradykinin (BK) receptor stimulation causes phosphoinositide hydrolysis and release of inositol phosphates. Maximum stimulation (4-fold) of [2-3H]inositol trisphosphate (IP3) release in the absence of Li+ from NCB-20's prelabelled for 20-24 hours with [2-3H]myo-inositol (15 microCi/confluent 60mm dish) occurred after 5-10 seconds of bradykinin exposure, with an EC50 of approximately 100nM. Inositol bisphosphate (IP2) and inositol monophosphate (IP1) also showed increases (2.9-fold and 1.5 fold, respectively), with peaks at 15-20 seconds and 50 seconds, respectively. Under these same conditions, D-Ala2-D-Leu5 enkephalin (DADLE) (10 microM), an opiate agonist with 2nM affinity, gave no stimulation of IP3 release. Furthermore, it did not block BK-initiated release, both when applied simultaneously with BK and when cells were preincubated with DADLE for 100 minutes to lower cyclic AMP levels. These results show that pain-inducing BK has a major acute stimulatory effect on receptor-phospholipase C-coupled IP3 release, the opioid peptide DADLE has no such effect and, DADLE does not block the IP3 release induced by BK.
D000818:Animals; D001920:Bradykinin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D001921:Brain; D002460:Cell Line; D002999:Clone Cells; D006224:Cricetinae; D003412:Cricetulus; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives* / Q000494:pharmacology; D016308:Enkephalin, Leucine-2-Alanine; D006822:Hybrid Cells; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000378:metabolism*; D051379:Mice; D009447:Neuroblastoma; D009474:Neurons / Q000378:metabolism*; D013403:Sugar Phosphates / Q000378:metabolism*
D007295:Inositol Phosphates; D013403:Sugar Phosphates; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine; D015544:Inositol 1,4,5-Trisphosphate; D001920:Bradykinin