Format

Send to

Choose Destination
Br J Pharmacol. 1999 Sep;128(1):1-3.

Characterization of recombinant human orexin receptor pharmacology in a Chinese hamster ovary cell-line using FLIPR.

Author information

1
Neuroscience Research, SmithKline Beecham Pharmaceuticals, New Frontiers Science Park, Third Avenue, Harlow, Essex CM19 5AW, UK. Darren_2_Smart@sbphrd.com

Abstract

The cellular mechanisms underlying the physiological effects of the orexins are poorly understood. Therefore, the pharmacology of the recombinant human orexin receptors was studied using FLIPR. Intracellular calcium ([Ca2+]i) was monitored in Chinese hamster ovary (CHO) cells stably expressing orexin-1 (OX1) or orexin-2 (OX2) receptors using Fluo-3AM. Orexin-A and orexin-B increased [Ca2+]i in a concentration dependent manner in CHO-OX1 (pEC50=8.03+/-0.08 and 7. 30+/-0.08 respectively, n=5) and CHO-OX2 (pEC50=8.18+/-0.10 and 8. 43+/-0.09 respectively, n=5) cells. This response was typified as a rapid peak in [Ca2+]i (maximal at 6 - 8 s), followed by a gradually declining secondary phase. Thapsigargin (3 microM) or U73122 (3 microM) abolished the response. In calcium-free conditions the peak response was unaffected but the secondary phase was shortened, returning to basal values within 90 s. Calcium (1.5 mM) replacement restored the secondary phase. In conclusion, orexins cause a phospholipase C-mediated release of calcium from intracellular stores, with subsequent calcium influx.

PMID:
10498827
PMCID:
PMC1571615
DOI:
10.1038/sj.bjp.0702780
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center