A Putative Cation Channel and Its Novel Regulator: Cross-Species Conservation of Effects on General Anesthesia

Curr Biol. 2007 Apr 3;17(7):624-9. doi: 10.1016/j.cub.2007.02.037. Epub 2007 Mar 15.

Abstract

Volatile anesthetics like halothane and enflurane are of interest to clinicians and neuroscientists because of their ability to preferentially disrupt higher functions that make up the conscious state. All volatiles were once thought to act identically; if so, they should be affected equally by genetic variants. However, mutations in two distinct genes, one in Caenorhabditis and one in Drosophila, have been reported to produce much larger effects on the response to halothane than enflurane [1, 2]. To see whether this anesthesia signature is adventitious or fundamental, we have identified orthologs of each gene and determined the mutant phenotype within each species. The fly gene, narrow abdomen (na), encodes a putative ion channel whose sequence places it in a unique family; the nematode gene, unc-79, is identified here as encoding a large cytosolic protein that lacks obvious motifs. In Caenorhabditis, mutations that inactivate both of the na orthologs produce an Unc-79 phenotype; in Drosophila, mutations that inactivate the unc-79 ortholog produce an na phenotype. In each organism, studies of double mutants place the genes in the same pathway, and biochemical studies show that proteins of the UNC-79 family control NA protein levels by a posttranscriptional mechanism. Thus, the anesthetic signature reflects an evolutionarily conserved role for the na orthologs, implying its intimate involvement in drug action.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anesthesia, General*
  • Anesthetics, Inhalation / pharmacology
  • Animals
  • Biological Evolution
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism
  • Cytosol / chemistry
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / metabolism*
  • Enflurane / pharmacology
  • Halothane / pharmacology
  • Ion Channels / genetics
  • Ion Channels / metabolism*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Molecular Sequence Data
  • Mutation
  • Phenotype

Substances

  • Anesthetics, Inhalation
  • Caenorhabditis elegans Proteins
  • Drosophila Proteins
  • Ion Channels
  • Membrane Proteins
  • Na protein, Drosophila
  • Unc-79 protein, C elegans
  • unc79 protein, Drosophila
  • Enflurane
  • Halothane

Associated data

  • GENBANK/AY555271
  • GENBANK/AY555272
  • GENBANK/DQ858354
  • GENBANK/DQ917240
  • GENBANK/DQ917241
  • GENBANK/DQ923614