ISSN:
1432-2013
Keywords:
Osteoblast
;
Cl-conductance
;
Cyclic-AMP
;
Parathyroid hormone
;
Cystic fibrosis
;
Ca-current
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract In primary cultures of rat osteoblasts, studied with the whole-cell configuration of the patch-clamp technique, 8-bromo-cyclic AMP (8BrcAMP) forskolin (FS) and 1–34 parathyroid hormone (PTH) were shown to activate a Cl conductance. This conductance shows a pronounced outward rectification, even with symmetrical Cl concentrations. It is blocked partially and reversibly by 4,4′-diisothiocyanatostilbene 2,2′-disulfonic acid (DIDS) or diphenylcarboxylate (DPC). The blockade induced by DIDS is time-and voltage-dependent. The Cl responses to FS and PTH develop slowly, after a delay of several seconds and are very slowly reversible. These responses were observed only in a fraction of the cells tested and their detection was favoured by cell dialysis. This Cl current should be taken into account for studying possible modulations of the voltage-gated Ca currents of osteoblasts. It is suggested that its physiological role may be related to the well-known morphological changes induced by PTH in osteoblasts. The cyclic AMP-sensitivity, the outward rectification and the sensitivity to dialysis of this Cl current are reminiscent of the properties of the cystic fibrosis-sensitive Cl channels of epithelial cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00373147
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