In:
British Journal of Pharmacology, Wiley, Vol. 131, No. 6 ( 2000-11), p. 1195-1203
Abstract:
Brain capillary endothelial cells express a variety of nucleotide receptors, but differences have been reported between culture models. This study reports examination of nucleotide receptors on primary cultured rat brain capillary endothelial cells (RBCEC) grown on a biological extracellular matrix (ECM) to produce a more differentiated phenotype. Fura‐2 fluorescence ratio imaging was used to monitor intracellular free calcium concentration [Ca 2+ ] i . ATP, UTP, and 2‐methylthioATP (2‐MeSATP) increased [Ca 2+ ] i to similar levels, while 2‐MeSADP, ADP and adenosine gave smaller responses. Removal of extracellular calcium caused no significant change in the [Ca 2+ ] i response to 2‐MeSATP, evidence that the response was mediated by a metabotropic (P2Y) receptor. All cells tested responded to ATP, UTP, 2‐MeSATP and ADP, while 63% responded to adenosine and 50% to 2‐MeSADP. No cells responded to α,β‐methyleneATP. Cells grown on rat tail collagen instead of ECM gave smaller and less uniform [Ca 2+ ] i responses, suggesting that the differentiating effect of the ECM contributed to a more uniform receptor profile. The [Ca 2+ ] i response to the P2Y 1 ‐selective agonist 2‐MeSADP was abolished in the presence of the subtype‐selective antagonist adenosine 3′‐phosphate 5′‐phosphosulphate (PAPS). The P2Y 2 antagonist suramin completely blocked the response to ATP and inhibited the response to UTP by 66%. The A 1 subtype‐selective adenosine receptor agonist N 6 ‐Cyclopentyladenosine (CPA) gave a small but characteristic [Ca 2+ ] i response, while A 2A and A 2B subtype‐selective agonists failed to generate [Ca 2+ ] i changes. The results are consistent with the presence on RBCEC of a P2Y 2 ‐like receptor coupled to phospholipase C, and a P2Y 1 ‐like receptor mobilizing intracellular Ca 2+ . The role of multiple nucleotide receptors in the function of the brain endothelium is discussed. British Journal of Pharmacology (2000) 131 , 1195–1203; doi: 10.1038/sj.bjp.0703675
Type of Medium:
Online Resource
ISSN:
0007-1188
,
1476-5381
DOI:
10.1038/sj.bjp.0703675
Language:
English
Publisher:
Wiley
Publication Date:
2000
detail.hit.zdb_id:
2029728-2
SSG:
15,3
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