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Review
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Korean J Med. 2006;71(1):245-245.
- The Actions of Bradykinin in Murine Small Intestinal Motility by Modulating Pacemaker Currents in Cultured Interstitial Cells of Cajal through Bradykinin B2 Receptors
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Bum-Ju, Lee, Jong-Chan Oh, Jae-Hyun Jang, Kyung-Jun Won, Chan-Guk Park, Man-Woo Kim, Seok Choi, Jae-Yeoul Jun
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- The Actions of Bradykinin in Murine Small Intestinal Motility by Modulating Pacemaker Currents in Cultured Interstitial Cells of Cajal through Bradykinin B2 Receptors
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중앙대학교 병원 내과학교실, 비뇨기과 교실, Cell genomics
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- Abstract
- We studied the modulation of pacemaker activities by bradykinin in cultured interstitial Cells of Cajal (ICC) from murine small
intestine with the whole cell patch-clamp technique. Externally applied bradykinin produced membrane depolarization in the
current-clamp mode and increased tonic inward pacemaker currents in the voltage-clamp mode. Pretreatment with bradykinin
B1 antagonist did not block the bradykinin-induced effects on pacemaker currents. But, pretreatment with bradykinin B2
antagonist selectively blocked the bradykinin-induced effects. Also, only externally applied selective bradykinin B2 receptor
agonist produced tonic inward pacemaker currents and ICC revealed a co-localization of the bradykinin B2 receptors and c-kit
immunoreactivity but bradykinin B1 receptors did not localize in ICC. External Na+ - free solution abolished the generation of
pacemaker currents and inhibited the bradykinin-induced tonic inward current. However, a Cl- channel blocker (DIDS) did not
block the bradykinin-induced tonic inward current. The pretreatment with Ca2+ free solution and thapsigargin, a Ca2+ -ATPase
inhibitor in endoplasmic reticulum, abolished the generation of pacemaker currents and suppressed the bradykinin-induced action.
Chelerythrine and calphostin C, protein kinase C inhibitors or naproxen, an inhibitor of cyclooxygenase, did not block the
bradykinin-induced effects on pacemaker currents. These results suggest that bradykinin modulates the pacemaker activities
through bradykinin B2 receptor activation in ICC by external Ca2+ influx and internal Ca2+ release via protein kinase C- or
cyclooxygenase-independent mechanism. Therefore, the ICC are targets for bradykinin and their interaction can effect on
intestinal motility. Keywords : Interstitial cells of Cajal ; Pacemaker currents; bradykinin; Bradykinin B2 receptors; Intestinal
motility
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