Heparin inhibits the inositol 1,4,5-trisphosphate-dependent, but not the independent, calcium release induced by guanine nucleotide in vascular smooth muscle

https://doi.org/10.1016/S0006-291X(88)81141-0Get rights and content
Under a Creative Commons license
open archive

Summary

The effects of heparin on the release of intracellular Ca2+, assessed by tension development in saponin-permeabilized rabbit main pulmonary artery, were determined. Heparin inhibited (IC50 = 5μg/ml) inositol2+ 1,4,5-trisphosphate (InsP3)-induced, but not caffeine-induced, Ca2+ release. The initial (InsP3-dependent) component of GTPγS-induced Ca2+-release was also inhibited by heparin, but the InsP3-independent component was resistant to both heparin and procaine. These results support the existence of a G protein activated mechanism of Ca2+ release that is not mediated by InsP3 or by Ca2+-induced Ca2+ release.

Abbreviations

InsP3
inositol 1,4,5-trisphosphate
G protein
guaninenucleotide binding protein
SR
sarcoplasmic reticulum
GTPγS
Guanosine 5′-[gl-thio]triphosphate
MPA
main pulmonary artery

Cited by (0)