Effects of adenosine on guinea pig pulmonary eosinophils.
Extracellular adenosine has pharmacological activity on a wide variety of cell types and may play an important role as an inflammatory modulator with both pro- and anti-inflammatory activities. These studies examine the effects of adenosine on guinea pig pulmonary eosinophils. Adenosine alone did not directly induce superoxide (O2-) production. Pretreatment with adenosine primed the O2- response of guinea pig pulmonary eosinophils following the addition of 1 or 10 microM platelet-activating factor (PAF). Priming was seen at adenosine concentrations greater than 1 microM and was maximal at 100 microM. At this maximal dose, adenosine priming increased the O2- response to 1 microM and 10 microM PAF by 86% and 51%, respectively. Priming by adenosine was not seen when ionomycin or phorbol myristate acid (PMA) were used as agonists. In fura-2 loaded eosinophils, the addition of 100 microM adenosine resulted in a small but significant rise in intracellular calcium of 54.4 +/- 9.2 nM above baseline. In contrast, similar adenosine concentrations had no effect on cytosolic calcium levels in guinea pig neutrophils. These data demonstrate a pro-inflammatory role for adenosine in elicited guinea pig pulmonary eosinophils.
Walker
B A
BA
U.B.C. Pulmonary Research Laboratory, University of British Columbia, Vancouver British Columbia, Canada.
D000241:Adenosine / Q000819:agonists / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D004804:Eosinophils / Q000187:drug effects* / Q000378:metabolism; D006168:Guinea Pigs; D015759:Ionomycin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D008168:Lung / Q000473:pathology*; D010972:Platelet Activating Factor / Q000494:pharmacology; D018047:Receptors, Purinergic P1 / Q000187:drug effects / Q000502:physiology; D012130:Respiratory Hypersensitivity / Q000473:pathology; D013481:Superoxides / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007476:Ionophores; D010972:Platelet Activating Factor; D018047:Receptors, Purinergic P1; D013481:Superoxides; D015759:Ionomycin; D000241:Adenosine; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium