ISSN:
1432-1424
Keywords:
Patch clamping
;
neuroblastoma cells
;
PKC
;
80K/MARCKS
;
muscarinic acetylcholine receptors
;
delayed rectifier
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary Differentiated neuroblastoma cells exhibit both the delayed rectifier potassium current (I K) and the M-current (I M). The present study was designed to determine the roles of protein kinase C (PKC) and of the calmodulin-binding protein 80K/MARCKS, a prominent substrate for PKC and possible regulator of these currents. Neuroblastoma x glioma (NG108-15) hybrid cells transfected with m1 muscarinic receptors were grown with 1% fetal bovine serum (FBS) without the prostaglandin E1 (PGE1) and isobutylmethylxanthine (IBMX) usually added in preparation for electrophysiological studies. Under these conditions, the usual pleomorphism was largely abolished, leaving two populations of small cells with stellate and spherically symmetrical geometries. Whole-cell patch clamping indicated that the two cell types had identical electrophysiological properties, displaying: I k, a small current through a “T-like” Ca2+ channel, and no M-current. Stimulation with carbachol shifted the distribution of cells to a more stellate morphology within 24 hr and later (after 48 hr) reduced the PKC substrate 80K/MARCKS by 22±7%. In contrast to the stimulation of I k observed with cardiac cells, PKC activation produced only a small inhibition of I k, which was independent of carbachol pretreatment. Thus, PKC and 80K/MARCKS can be dissociated from the regulation of I k in neuroblastoma cells. Supported in part by research grants from the National Institutes of Health (DK-40145 and EY-08343) and from the U.K. Medical Research Council.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00231877
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