P2‐purinoceptor‐stimulated phosphoinositide turnover in chick myotubes calcium mobilization and the role of guanyl nucleotide‐binding proteins

FEBS Letters

Heilbronn, Edith¹  Häggblad, Johan¹ 

[1] Unit of Neurochemistry and Neurotoxicology, University of Stockholm, S-106 91 Stockholm, Sweden

关键词: P2-purinoceptor;    ATP;    Inositol phosphate;    cytosolic Ca2+;    Quin-2;    Myotube;   

DOI  :  10.1016/0014-5793(88)81248-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

ATP, a trigger of P2-purinoceptor-mediated polyphosphoinositide (PI) turnover in cultured myotubes, increased cytosolic calcium levels in a time- and dose-dependent manner (quin2 fluorescence). The calcium was released from intracellular stores, as acute addition of 5 mM EGTA was without significant effect. Adenosine 5′-(3-thiotriphosphate) and 5′-adenylyl imidodiphosphate also increased intracellular levels of inositol phosphates (InsP) and cytosolic calcium levels. Treatment with cholera or pertussis toxin of myotube cultures did not affect the P2-purinoceptor-mediated InsP increase although PI turnover in permeabilized myotubes was stimulated by guanosine 5′-(3-thiotriphosphate). The results suggest that myotube P2-purinoceptors trigger PI turnover and increase intracellular free calcium levels, via a mechanism insensitive to ADP-ribosylation, by cholera or pertussis toxin of guanyl nucleotide-binding (G) proteins. However, the presence of a phospholipase C-coupled G-protein was otherwise demonstrated.

【 授权许可】

Unknown