Human neutrophils have a novel purinergic P2-type receptor linked to calcium mobilization.
Stimulation of suspensions of fura-2-loaded human neutrophils with ATP resulted in an elevation in cytosolic free calcium concentration ([Ca2+]i) from a basal value of 0.1 microM to a transient peak of 1 microM. The response is due to Ca2+ release from intracellular stores and influx of extracellular Ca2+. Release from intracellular stores is shown by the response in the absence of extracellular Ca2+. The greater and more maintained response in the presence of extracellular Ca2+ is indicative of stimulated Ca2+ entry and a stimulated influx pathway was confirmed by using Mn2+ as a surrogate for Ca2+. A variety of purinergic agonists were used to characterize the pharmacology of this [Ca2+]i response. Their rank order of potency was ATP greater than adenosine 5'-O-(3-thiotriphosphate) (ATP gamma S) greater than ADP much greater than 2-methylthioadenosine 5'-triphosphate (2Me-SATP), where ATP had an EC50 value of 3 microM and 2MeSATP had an EC50 value of 1000 microM. Adenosine 5'-O-(2-thiodiphosphate) (ADP beta S), adenylyl (alpha,beta-methylene)- diphosphonate (AMPCPP) and adenosine were inactive at 1 mM. These results suggest that neutrophils have a novel type of purinergic P2 receptor that is neither P2x nor P2y.
Merritt
J E
JE
SmithKline Beecham Pharmaceuticals, The Frythe, Welwyn, Herts, U.K.
Moores
K E
KE
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004912:Erythrocytes / Q000201:enzymology; D016257:Fura-2; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism*; D011983:Receptors, Purinergic / Q000378:metabolism*; D014422:Turkeys; D010738:Type C Phospholipases / Q000378:metabolism
D011983:Receptors, Purinergic; D009240:N-Formylmethionine Leucyl-Phenylalanine; D000255:Adenosine Triphosphate; D010738:Type C Phospholipases; D002118:Calcium; D016257:Fura-2