CALCIUM REQUIREMENTS FOR REGULATORY EFFECTS OF ATP, ATPyS AND ADENOSINE ON 0; RESPONSES OF HUMAN NEUTROPHILS
نویسندگان
چکیده
In formyl peptide stimulated human neutrophils the enhancement of 05 responses by ATP and ATPyS requires extracellular calcium. In contrast, the inhibitory effects of adenosine are independent of a calcium requirement. Rates of 0: generation are not affected by these adenine compounds. Rather, ATP and AT?$ cause a sustained period of generation whereas adenosine causes an abrupt early termination of the 0; response. The differing calcium requirements for regulatory effects of adenine compounds on 0: responses of stimulated neutrophils suggests that ATP (or ATPyS) and adeno ine may exert 5 their effects at different points in the pathway of signal transduction events. D 1988 Rcademlc PtTS5, 1°C.
منابع مشابه
Functional Consequences of Interactions between Human Neutrophils and ATP, ATPyS, and Adenosine“
There is an increasing body of evidence suggesting that nucleotides such as ATP can serve as important extracellular factors to bring about significant functional changes in phagocytic cells. For instance, ATP and its analogues (for example, adenosine-5‘-0-( 3-thiotriphosphate), or ATPyS) can interact with neutrophils to cause increases in intracellular calcium.14 This appears to be associated ...
متن کاملStructural requirements for binding of adenosine-5'-O-(3-thiotriphosphate) (ATPTS) to human neutrophils
Human polymorphonuclear leukocytes (PMN) respond via pertussis toxin-sensitive pathways to extracellular nucleotides with an elevation in intracellular calcium ([Ca 2+ ]i) and enhancement of the O~generation induced by the chemotactic peptide N'-formyl-Met-Leu-Phe (fMLP). Binding studies with adenosine 5'-O-(3-thio[aSS]triphosphate) ([35S]ATPyS) have recently identified at least two classes of ...
متن کاملInhibition of RecA Protein Promoted ATP Hydrolysis. 1. ATPrS and ADP Are Antagonistic Inhibitors?
A D P and adenosine 5’-04 3-thiotriphosphate) (ATPyS) inhibit recA protein promoted ATP hydrolysis by fundamentally different mechanisms. In both cases, a t least two modes of inhibition are observed. For ADP, the first mode is competitive inhibition. The second mode is manifested by dissociation of recA protein from DNA. These are readily distinguished in a comparison of A T P hydrolyses that ...
متن کاملReactivity and metal-dependent stereospecificity of the phosphorothioate analogs of ATP in the arginine kinase reaction. Structure of the metal-nucleoside triphosphate substrate.
The kinetic parameters K M and V,, have been determined in the reaction catalyzed by lobster muscle arginine kinase for ATP, adenosine 5'-0-(34hiotriphosphate) (ATPyS), the diastereomers of adenosine 5'-0(2-thiotriphosphate) (ATPBS), and the diastereomers of adenosine 5'-O-(l-thiotriphosphate) (ATPaS) with Mg(I1) or Cd(I1) as activating ions. With Mg(II), the Rp diastereomers of both ATP& and A...
متن کاملThe regulation of bone cell function by extracellular nucleotides
Extracellular nucleotides, acting via P2 receptors, modulate bone remodelling by inhibiting osteoblast and stimulating osteoclast activity. The aim of this thesis was to investigate further the effects of extracellular nucleotides on bone cell function under both normal and stress situations. Nucleotide agonists were shown to evoke intracellular Ca2+ responses in rat osteoblasts from >0.2 |nM. ...
متن کامل