In:
American Journal of Physiology-Cell Physiology, American Physiological Society, Vol. 273, No. 5 ( 1997-11-01), p. C1721-C1731
Abstract:
Two populations, Ca 2+ -dependent (BK Ca ) and Ca 2+ -independent K + (BK) channels of large conductance were identified in inside-out patches of nonlabor and labor freshly dispersed human pregnant myometrial cells, respectively. Cell-attached recordings from nonlabor myometrial cells frequently displayed BK Ca channel openings characterized by a relatively low open-state probability, whereas similar recordings from labor tissue displayed either no channel openings or consistently high levels of channel activity that often exhibited clear, oscillatory activity. In inside-out patch recordings, Ba 2+ (2–10 mM), 4-aminopyridine (0.1–1 mM), and Shaker B inactivating peptide (“ball peptide”) blocked the BK Ca channel but were much less effective on BK channels. Application of tetraethylammonium to inside-out membrane patches reduced unitary current amplitude of BK Ca and BK channels, with dissociation constants of 46 mM and 53 μM, respectively. Tetraethylammonium applied to outside-out patches decreased the unitary conductance of BK Ca and BK channels, with dissociation constants of 423 and 395 μM, respectively. These results demonstrate that the properties of human myometrial large-conductance K + channels in myocytes isolated from laboring patients are significantly different from those isolated from nonlaboring patients.
Type of Medium:
Online Resource
ISSN:
0363-6143
,
1522-1563
DOI:
10.1152/ajpcell.1997.273.5.C1721
Language:
English
Publisher:
American Physiological Society
Publication Date:
1997
detail.hit.zdb_id:
1477334-X
SSG:
12
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