title: Characteristics of the cholecystokinin-induced depolarization of pacemaking activity in cultured interstitial cells of Cajal from murine small intestine.
abstract: OBJECTIVE
  In this study, we studied the effects of cholecystokinin (CCK) on pacemaker potentials in cultured interstitial cells of Cajal (ICCs) from mouse small intestine using the whole cell patch clamp technique.
  
  
  METHODS
  ICCs are pacemaker cells that exhibit periodic spontaneous depolarization, which is responsible for the production of slow waves in gastrointestinal smooth muscle, and generate periodic pacemaker potentials in current-clamp mode.
  
  
  RESULTS
  Exposure to CCK (100 nM-5 µM) decreased the amplitudes of pacemaker potentials and depolarized resting membrane potentials. To identify the type of CCK receptors involved in ICCs, we examined the effects of CCK agonists and found that the addition of CCK1 agonist (A-71323, 1 µM) depolarized resting membrane potentials, whereas exposure to CCK2 agonist (gastrin, 1 µM) had no effect on pacemaker potentials. To confirm these results, we examined the effects of CCK antagonists and found that pretreatment with CCK1 antagonist (SR 27897, 1 µM) blocked CCK-induced effects. However, pretreatment with CCK2 antagonist (LY 225910, 1 µM) did not. Furthermore, intracellular GDPβS suppressed CCK-induced effects. To investigate the involvements of phospholipase C (PLC), protein kinase C (PKC), and protein kinase A (PKA) in the effects of CCK in cultured ICCs, we used U-73122 (an active PLC inhibitor), chelerythrine (a PKC inhibitor), SQ-22536 (an inhibitor of adenylate cyclase), or mPKAI (an inhibitor of myristoylated PKA). All inhibitors blocked the CCK-mediated effects on pacemaker potentials. In addition, we found that transient receptor potential classical 5 (TRPC5) channel was involved in CCK-activated currents in cultured ICCs.
  
  
  CONCLUSIONS
  These results suggest that the CCK induced depolarization of pacemaking activity occurs in a G-protein-, PLC-, PKC-, and PKA-dependent manner via CCK1 receptor and TRPC5 channel is a candidate for CCK-activated currents in cultured ICCs in murine small intestine. Therefore, the ICCs are targets for CCK and their interaction can affect intestinal motility.
authors.affiliation: Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Jae Hwa
authors.initials: JH
authors.lastname: Lee
authors.forename: Sung-Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Young Kyu
authors.initials: YK
authors.lastname: Kwon
authors.forename: Byung Joo
authors.initials: BJ
authors.lastname: Kim
authors.forename: Insuk
authors.initials: I
authors.lastname: So
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D019742:Chemokines, CC; D002766:Cholecystokinin / Q000494:pharmacology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004963:Estrenes / Q000494:pharmacology; D005755:Gastrins / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000494:pharmacology; D056885:Interstitial Cells of Cajal / Q000166:cytology / Q000378:metabolism*; D007421:Intestine, Small / Q000166:cytology / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D018408:Patch-Clamp Techniques; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D011760:Pyrrolidinones / Q000494:pharmacology; D052999:Quinazolinones / Q000494:pharmacology; D043887:Receptor, Cholecystokinin B / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D011949:Receptors, Cholecystokinin / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D050052:TRPC Cation Channels / Q000378:metabolism; D013844:Thiazoles / Q000494:pharmacology; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: C435663:2-(2-(5-bromo-1H-indol-3-yl)ethyl)-3-(1-methylethoxyphenyl)-4-(3H)-quinazolinone; C511142:Ccl28 protein, mouse; D019742:Chemokines, CC; D004963:Estrenes; D005755:Gastrins; D007210:Indoleacetic Acids; D011760:Pyrrolidinones; D052999:Quinazolinones; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin; D050052:TRPC Cation Channels; D013844:Thiazoles; C112021:Trpc5 protein, mouse; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C080460:SR 27897; D002766:Cholecystokinin; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D010738:Type C Phospholipases