{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,18]],"date-time":"2026-03-18T12:51:04Z","timestamp":1773838264637,"version":"3.50.1"},"reference-count":0,"publisher":"Oxford University Press (OUP)","issue":"2","license":[{"start":{"date-parts":[[1990,2,1]],"date-time":"1990-02-01T00:00:00Z","timestamp":633830400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[1990,2,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Because adenosine narrows asthmatic airways, is released during hypoxia and by mast cells, and is antagonized by theophylline, it may play a role in asthma. I characterized the first step in pulmonary responses to adenosine: its adenosine receptor. Plasma membranes, prepared from macroscopically normal human peripheral lung, were incubated with 10 nM 5\u2032-N-ethylcarboxamido[3H]adenosine ([3H]NECA) and various concentrations of competing ligand under experimentally determined optimal conditions: 4\u00b0 C, pH 7.4, 5 mM MgCl2, 1.8 mg protein\/ml, 30-min incubation time. Bound and free ligand were separated by rapid vacuum filtration, and the radioactive counts were analyzed using a weighted, non-linear, least-squares curve-fitting program, LIGAND. Analyzed together, the data from the lungs of 6 patients revealed a single binding site with a dissociation constant (Kd) for NECA of 200 nM \u00b1 14% and a receptor concentration of 543 fmol\/mg protein \u00b1 13%. Analyzed separately, the individual Kds ranged from 133 to 430 nM and the receptor concentrations from 338 to 811 fmol\/mg protein. Adenosine receptor ligands competed with NECA in an A2 rank order of potency &amp;gt; NECA &amp;gt; 8-phenyltheophylline &amp;gt; 3-isobutyl-1-methylxanthine &amp;gt; theophylline &amp;gt; N6-L-phenylisopropyladenosine &amp;gt; N6-D-phenylisopropyladenosine &amp;gt; N6-cyclohexyladenosine. Theophylline bound to the receptor with an inhibition constant (Ki = 70.9 \u00b5M \u00b1 28%) near the therapeutic range (28 to 56 \u00b5M). Cromolyn also bound with high affinity (Ki = 5.42 \u00b5M \u00b1 47%). I conclude that human lung adenosine receptors: (1) are single-site receptors, probably of the A2 subtype and (2) bind to both theophylline and cromolyn.<\/jats:p>","DOI":"10.1165\/ajrcmb\/2.2.193","type":"journal-article","created":{"date-parts":[[2013,4,3]],"date-time":"2013-04-03T23:11:20Z","timestamp":1365030680000},"page":"193-198","source":"Crossref","is-referenced-by-count":16,"title":["Characterization of the Human Peripheral Lung Adenosine Receptor"],"prefix":"10.1093","volume":"2","author":[{"given":"Jesse P.","family":"Joad","sequence":"first","affiliation":[{"name":"Department of Pediatrics, University of California at Davis, Davis, California"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"286","published-online":{"date-parts":[[1990,2,1]]},"container-title":["American Journal of Respiratory Cell and Molecular Biology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/academic.oup.com\/ajrcmb\/article-pdf\/2\/2\/193\/67278894\/ajrcmb_2_2_193.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/ajrcmb\/article-pdf\/2\/2\/193\/67278894\/ajrcmb_2_2_193.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,3,18]],"date-time":"2026-03-18T09:26:30Z","timestamp":1773825990000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/ajrcmb\/article\/2\/2\/193\/8511921"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1990,2,1]]},"references-count":0,"journal-issue":{"issue":"2","published-online":{"date-parts":[[1990,2,1]]},"published-print":{"date-parts":[[1990,2,1]]}},"URL":"https:\/\/doi.org\/10.1165\/ajrcmb\/2.2.193","relation":{},"ISSN":["1044-1549","1535-4989"],"issn-type":[{"value":"1044-1549","type":"print"},{"value":"1535-4989","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[1990,2]]},"published":{"date-parts":[[1990,2,1]]}}}