PMID- 22130664
OWN - NLM
STAT- MEDLINE
DCOM- 20120315
LR  - 20211021
IS  - 1083-351X (Electronic)
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 287
IP  - 4
DP  - 2012 Jan 20
TI  - Molecular cloning and functional characterization of Xenopus tropicalis frog 
      transient receptor potential vanilloid 1 reveal its functional evolution for 
      heat, acid, and capsaicin sensitivities in terrestrial vertebrates.
PG  - 2388-97
LID - 10.1074/jbc.M111.305698 [doi]
AB  - The functional difference of thermosensitive transient receptor potential (TRP) 
      channels in the evolutionary context has attracted attention, but thus far little 
      information is available on the TRP vanilloid 1 (TRPV1) function of amphibians, 
      which diverged earliest from terrestrial vertebrate lineages. In this study we 
      cloned Xenopus tropicalis frog TRPV1 (xtTRPV1), and functional characterization 
      was performed using HeLa cells heterologously expressing xtTRPV1 (xtTRPV1-HeLa) 
      and dorsal root ganglion neurons isolated from X. tropicalis (xtDRG neurons) by 
      measuring changes in the intracellular calcium concentration ([Ca(2+)](i)). The 
      channel activity was also observed in xtTRPV1-expressing Xenopus oocytes. 
      Furthermore, we tested capsaicin- and heat-induced nocifensive behaviors of the 
      frog X. tropicalis in vivo. At the amino acid level, xtTRPV1 displays  approximately 60% 
      sequence identity to other terrestrial vertebrate TRPV1 orthologues. Capsaicin 
      induced [Ca(2+)](i) increases in xtTRPV1-HeLa and xtDRG neurons and evoked 
      nocifensive behavior in X. tropicalis. However, its sensitivity was extremely low 
      compared with mammalian orthologues. Low extracellular pH and heat activated 
      xtTRPV1-HeLa and xtDRG neurons. Heat also evoked nocifensive behavior. In oocytes 
      expressing xtTRPV1, inward currents were elicited by heat and low extracellular 
      pH. Mutagenesis analysis revealed that two amino acids (tyrosine 523 and alanine 
      561) were responsible for the low sensitivity to capsaicin. Taken together, our 
      results indicate that xtTRPV1 functions as a polymodal receptor similar to its 
      mammalian orthologues. The present study demonstrates that TRPV1 functions as a 
      heat- and acid-sensitive channel in the ancestor of terrestrial vertebrates. 
      Because it is possible to examine vanilloid and heat sensitivities in vitro and 
      in vivo, X. tropicalis could be the ideal experimental lower vertebrate animal 
      for the study of TRPV1 function.
FAU - Ohkita, Masashi
AU  - Ohkita M
AD  - Department of Veterinary Pharmacology, Faculty of Agriculture, Tottori 
      University, Tottori 680-8553, Japan.
FAU - Saito, Shigeru
AU  - Saito S
FAU - Imagawa, Toshiaki
AU  - Imagawa T
FAU - Takahashi, Kenji
AU  - Takahashi K
FAU - Tominaga, Makoto
AU  - Tominaga M
FAU - Ohta, Toshio
AU  - Ohta T
LA  - eng
SI  - GENBANK/AB682793
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20111130
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Amphibian Proteins)
RN  - 0 (Sensory System Agents)
RN  - 0 (TRPV Cation Channels)
RN  - S07O44R1ZM (Capsaicin)
SB  - IM
MH  - Amphibian Proteins/genetics/*metabolism
MH  - Animals
MH  - Base Sequence
MH  - Capsaicin/*pharmacology
MH  - Evoked Potentials/drug effects/physiology
MH  - *Evolution, Molecular
MH  - Ganglia, Spinal/cytology/*metabolism
MH  - HeLa Cells
MH  - Humans
MH  - Molecular Sequence Data
MH  - Oocytes/cytology
MH  - Pain/genetics/metabolism
MH  - Sensory System Agents/*pharmacology
MH  - TRPV Cation Channels/genetics/*metabolism
MH  - Taste/drug effects/*physiology
MH  - Thermosensing/drug effects/*physiology
MH  - Xenopus
PMC - PMC3268400
EDAT- 2011/12/02 06:00
MHDA- 2012/03/16 06:00
PMCR- 2013/01/20
CRDT- 2011/12/02 06:00
PHST- 2011/12/02 06:00 [entrez]
PHST- 2011/12/02 06:00 [pubmed]
PHST- 2012/03/16 06:00 [medline]
PHST- 2013/01/20 00:00 [pmc-release]
AID - S0021-9258(20)53201-8 [pii]
AID - M111.305698 [pii]
AID - 10.1074/jbc.M111.305698 [doi]
PST - ppublish
SO  - J Biol Chem. 2012 Jan 20;287(4):2388-97. doi: 10.1074/jbc.M111.305698. Epub 2011 
      Nov 30.