ISSN:
1432-2013
Keywords:
Inositol trisphosphate
;
Caged InsP 3
;
Caged ATP
;
Heparin
;
Calcium current
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract In single cells obtained by enzymic treatment of rabbit small-intestinal smooth muscle, and held under voltage clamp by patch pipette in the whole-cell recording mode, release of inositol trisphosphate (InsP 3) from its caged precursor by flash photolysis caused complete inhibition of the voltage-dependent calcium current. No inhibition was seen in control experiments where the cage (2-nitrosoacetophenone) was released by flash photolysis from caged ATP. The inhibition by InsP 3 of the calcium current was prevented if 10 mM EGTA or 2 mg/ml heparin was included in the pipette solution. Heparin is known to block InsP 3 receptors. These results suggest that release of calcium stores by InsP 3 raises Cai and that calcium ions inhibit the calcium current by acting either directly or otherwise on the internal mouth of the calcium channel.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00497770
Permalink
