Protein kinase C mediates the desensitization of CCh-activated nonselective cationic current in guinea-pig gastric myocytes
In: Pflugers Archiv : European journal of physiology, Jg. 436 (1998-06-20), Heft 1
Online
unknown
Zugriff:
The possibility of the protein kinase C (PKC) pathway being a mechanism underlying the desensitization of carbachol- (CCh-)activated nonselective cationic current (ICCh) was investigated in a study of guinea-pig gastric myocytes. Using the conventional whole-cell patch-clamp technique with symmetrical CsCl-rich solution in pipette and bath, ICCh was induced by bath application of 50 microM CCh. With 0.5 mM EGTA [ethyleneglycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid] in the pipette solution (0.5 mM [EGTA]i), ICCh decayed spontaneously (desensitization of ICCh) to around 20% within 10 min. Desensitization of ICCh was significantly attenuated with 2 mM [EGTA]i. At a concentration of 20 microM OAG (1-oleoyl-2-acetyl-sn-glycerol), a PKC activator, inhibited ICCh at 0.5 mM [EGTA]i but far less at 2 mM [EGTA]i (18% and 81% of control, respectively). The same cationic current induced by intracellular guanosine-5'-O-(3-thiotriphosphate) (GTP[gamma-S]) was not inhibited by OAG with 0.5 mM [EGTA]i. The pretreatment of gastric myocytes with PKC inhibitors, either 1 microM chelerythrine or 1 microM peptide inhibitor, attenuated the desensitization of ICCh. [Ca2+]i was also measured by single cell microfluorometry using fura-2. Under CCh stimulation with 2 mM [EGTA]i, [Ca2+]i did not increase above 100 nM while it increased to around 260 nM with 0.5 mM [EGTA]i. These results suggest that the desensitization of ICCh is partly due to the Ca2+-dependent PKC pathway in guinea-pig gastric myocytes.
Titel: |
Protein kinase C mediates the desensitization of CCh-activated nonselective cationic current in guinea-pig gastric myocytes
|
---|---|
Autor/in / Beteiligte Person: | Jae Hoon Sim ; Tong Mook Kang ; Suk Hyo Suh ; So, Insuk ; Sung Joon Kim ; Jae Yeoul Jun ; Young Chul Kim ; Ki Whan Kim |
Link: | |
Zeitschrift: | Pflugers Archiv : European journal of physiology, Jg. 436 (1998-06-20), Heft 1 |
Veröffentlichung: | 1998 |
Medientyp: | unknown |
ISSN: | 0031-6768 (print) |
Schlagwort: |
|
Sonstiges: |
|