Characterisation using FLIPR of human vanilloid VR1 receptor pharmacology.
A full pharmacological characterisation of the recently cloned human vanilloid VR1 receptor was undertaken. In whole-cell patch clamp studies, capsaicin (10 microM) elicited a slowly activating/deactivating inward current in human embryonic kidney (HEK293) cells stably expressing human vanilloid VR1 receptor, which exhibited pronounced outward rectification (reversal potential -2.1+/-0.2 mV) and was abolished by capsazepine (10 microM). In FLIPR-based Ca(2+) imaging studies the rank order of potency was resiniferatoxin>olvanil>capsaicin>anandamide, and all were full agonists. Isovelleral and scutigeral were inactive (1 nM-30 microM). The potencies of capsaicin, olvanil and resiniferatoxin, but not anandamide, were enhanced 2- to 7-fold at pH 6.4. Capsazepine, isovelleral and ruthenium red inhibited the capsaicin (100 nM)-induced Ca(2+) response (pK(B)=6.58+/-0.02, 5.33+/-0.03 and 7.64+/-0.03, respectively). In conclusion, the recombinant human vanilloid VR1 receptor stably expressed in HEK293 cells acted as a ligand-gated, Ca(2+)-permeable channel with similar agonist and antagonist pharmacology to rat vanilloid VR1 receptor, although there were some subtle differences.
Smart
D
D
Neuroscience Research, SmithKline Beecham Pharmaceuticals, New Frontiers Science Park, Third Avenue, Essex CM19 5AW, Harlow, UK. Darren_2_Smart@sbphrd.com
Jerman
J C
JC
Gunthorpe
M J
MJ
Brough
S J
SJ
Ranson
J
J
Cairns
W
W
Hayes
P D
PD
Randall
A D
AD
Davis
J B
JB
D000470:Alkaloids; D000814:Aniline Compounds; D001095:Arachidonic Acids / Q000494:pharmacology; D053119:Benzophenanthridines; D002118:Calcium / Q000378:metabolism; D002211:Capsaicin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002460:Cell Line; D004224:Diterpenes / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D063388:Endocannabinoids; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005453:Fluorescence; D005470:Fluorometry / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008564:Membrane Potentials / Q000187:drug effects; D010617:Phenanthridines / Q000494:pharmacology; D000081223:Polycyclic Sesquiterpenes; D053284:Polyunsaturated Alkamides; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011955:Receptors, Drug / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D012430:Ruthenium Red / Q000494:pharmacology; D012717:Sesquiterpenes / Q000494:pharmacology; D013997:Time Factors; D014966:Xanthenes
D000470:Alkaloids; D000814:Aniline Compounds; D001095:Arachidonic Acids; D053119:Benzophenanthridines; D004224:Diterpenes; D063388:Endocannabinoids; D004791:Enzyme Inhibitors; D010617:Phenanthridines; D000081223:Polycyclic Sesquiterpenes; D053284:Polyunsaturated Alkamides; D011955:Receptors, Drug; D012717:Sesquiterpenes; D014966:Xanthenes; D012430:Ruthenium Red; C059715:Fluo-3; C089286:isovelleral; C054256:olvanil; C024353:resiniferatoxin; C016299:chelerythrine; D011493:Protein Kinase C; C071423:capsazepine; D002211:Capsaicin; D002118:Calcium; C078814:anandamide