Intracellular Ca2+ store-operated influx of Ca2+ through TRP-R, a rat homolog of TRP, expressed in Xenopus oocytes.
To elucidate whether rat transient receptor potential (TRP-R), a rat TRP4 homolog, functions as a store-operated Ca2+ channel (SOC), we have measured the Ca2+ entry after thapsigargin treatment in Xenopus oocytes injected with mRNA for TRP-R. While non-injected oocytes elicited an SOC response, significantly larger responses were observed in the oocytes expressing TRP-R. The oocyte-native SOC response was inhibited by injection of antisense oligodeoxyribonucleotide for mammalian TRP1. When Ca2+ concentration-SOC response curve was examined, the EC50 value was much smaller in oocytes expressing TRP-R than that of non-injected oocytes. These results suggest that TRP-R functions as SOC having higher sensitivity to external Ca2+ than amphibian TRP1 channel.
Tomita
Y
Y
Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Japan.
Kaneko
S
S
Funayama
M
M
Kondo
H
H
Satoh
M
M
Akaike
A
A
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology*; D020013:Calcium Signaling / Q000187:drug effects; D005656:Fungal Proteins / Q000235:genetics; D005822:Genetic Vectors; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism*; D051379:Mice; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D050052:TRPC Cation Channels; D019284:Thapsigargin / Q000494:pharmacology; D014981:Xenopus
D015220:Calcium Channels; D005656:Fungal Proteins; D050052:TRPC Cation Channels; C489571:TRPC4 ion channel; C096351:transient receptor potential cation channel, subfamily C, member 1; D019284:Thapsigargin; D002118:Calcium