Taghert PH et al. (2012) Neuron "Peptide neuromodulation in invertebrate model systems."

Nitabach MN, Taghert PH

[Neuron, 2012]

Neuropeptides modulate neural circuits controlling adaptive animal behaviors and physiological processes, such as feeding/metabolism, reproductive behaviors, circadian rhythms, central pattern generation, and sensorimotor integration. Invertebrate model systems have enabled detailed experimental analysis using combined genetic, behavioral, and physiological approaches. Here we review selected examples of neuropeptide modulation in crustaceans, mollusks, insects, and nematodes, with a particular emphasis on the genetic model organisms Drosophila melanogaster and Caenorhabditis elegans, where remarkable progress has been made. On the basis of this survey, we provide several integrating conceptual principles for understanding how neuropeptides modulate circuit function, and also propose that continued progress in this area requires increased emphasis on the development of richer, more sophisticated behavioral paradigms.

gphr

Golgi pH Regulator

alkaline pH chemotaxis variant

Animals exhibit variations in the characteristic movement towards typically attractive alkaline pH (pH higher than 7) compared to control. However animals tend to avoid very high pH levels (pH11). pH is a measure of the acidity or basicity of an aqueous solution. In C. elegans animals chemotax toward higher alkaline pH.

pwIs446

Caenorhabditis elegans

[Pvha-6::PH::GFP]

WBPaper00039779Ex2

Caenorhabditis elegans

[vha-6::ph::gfp]

fpIs13

Caenorhabditis elegans

[egl-26p::mCherry::PH]

cpIs122

Caenorhabditis elegans

[lag-2::mNeonGreen::PH]

orIs21

Caenorhabditis elegans

[pie-1p::GFP::PH]

pwIs890

Caenorhabditis elegans

[pvha6::Akt-PH::GFP]

Sanehisa, Shigeki et al. (2009) International Worm Meeting "C. elegans mutants defective in high-alkaline pH avoidance."

FUJIWARA, Mayuki, Sanehisa, Shigeki, Murayama, Takashi, MARUYAMA, Ichiro

[International Worm Meeting, 2009]

Cellular and molecular bases underlying nociception of high alkaline pH still remains to be explored. C. elegans senses higher alkaline pH ranges than ~pH 10.5 as a noxious stimulus. On an agar plate with a pH gradient, wild-type worms avoided higher pH regions, and moved toward lower pH ranges. To understand the molecular and cellular basis of the high-alkaline pH avoidance, we have screened mutants defective in high-alkaline pH avoidance from animals treated with ethylmethanesulfonate (EMS), using the plate assay. Among five mutants isolated that could not avoid the high-alkaline pH, three of them showed normal chemotaxis behaviors toward water-soluble attractants such as NaCl and mild-alkaline pH, as well as normal osmotic avoidance behaviors. We will discuss about molecules and neurons responsible for the nociception of high-alkaline pH.