Caenorhabditis elegans senses protons through amphid chemosensory neurons: proton signals elicit avoidance behavior.
Acidic pH is known to cause pain sensation through nociceptive neurons as well as taste transduction in mammals. Caenorhabditis elegans avoids an acidic environment (pH lower than approximately 4.0) formed by organic or inorganic acids. This avoidance behavior was dependent on multiple amphid chemosensory neurons, and inhibited by a mutation of capsaicin receptor homologue, and by the addition of amiloride and ruthenium red (inhibitors of proton-gated Na+ channels and capsaicin receptors, respectively). These results indicate that C. elegans recognizes protons as a nociceptive stimulus, through multiple neurons, which elicits avoidance behavior. It is of special interest that a system similar to that of mammalian signal transduction is responsible for this nematode's acid avoidance.
Sambongi
Y
Y
Division of Biological Sciences, The Institute of Scientific and Industrial Research, Osaka University, CREST of Japan Science and Technology Corporation, Ibaraki.
Takeda
K
K
Wakabayashi
T
T
Ueda
I
I
Wada
Y
Y
Futai
M
M
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001362:Avoidance Learning / Q000502:physiology*; D017173:Caenorhabditis elegans; D002628:Chemoreceptor Cells / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D009475:Neurons, Afferent / Q000502:physiology*; D010146:Pain; D011956:Receptors, Cell Surface; D011955:Receptors, Drug / Q000235:genetics / Q000502:physiology; D012430:Ruthenium Red / Q000494:pharmacology; D026941:Sodium Channel Blockers; D015222:Sodium Channels / Q000502:physiology
D011956:Receptors, Cell Surface; D011955:Receptors, Drug; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D012430:Ruthenium Red; D000584:Amiloride