Mutations of the caenorhabditis elegans brain-specific inorganic phosphate transporter eat-4 affect habituation of the tap-withdrawal response without affecting the response itself.
The studies reported here were designed to investigate the role of the mutation eat-4 in the response to tap and in habituation in the nematode Caenorhabditis elegans. In C. elegans eat-4 has been found to affect a number of glutamatergic pathways. It has been hypothesized to positively regulate glutaminase activity and therefore glutamatergic neurotransmission. In the eat-4(ky5) loss-of-function worms, there is presumably insufficient glutamate available for sustained transmission. In the experiments reported here eat-4 worms showed no differences from wild-type in the magnitude of response to a single tap, indicating that the neural circuit underlying the response was intact and functional in the mutant worms. However, when eat-4 worms were given repeated taps the resulting habituation was different from that seen in wild-type worms: eat-4 worms habituate more rapidly and recover more slowly than wild-type worms at all interstimulus intervals tested. In addition, eat-4 worms do not show dishabituation. The same transgene rescues pharyngeal activity defects and both the habituation and dishabituation deficits seen in the eat-4 worms. Our results suggest that neurotransmitter regulation plays a role in habituation and may play a role in dishabituation.
Rankin
C H
CH
Program in Neuroscience and Department of Psychology, University of British Columbia, Vancouver, British Columbia V6T-1Z4, Canada. crankin@cortex.psych.ubc.ca
Wicks
S R
SR
D000818:Animals; D001923:Brain Chemistry / Q000235:genetics* / Q000502:physiology*; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000502:physiology*; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D004597:Electroshock; D018698:Glutamic Acid / Q000502:physiology; D006185:Habituation, Psychophysiologic / Q000235:genetics* / Q000502:physiology*; D007700:Kinetics; D009154:Mutation / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology; D010614:Pharynx / Q000502:physiology; D028044:Phosphate-Binding Proteins; D010812:Physical Stimulation; D012018:Reflex / Q000235:genetics* / Q000502:physiology*; D009435:Synaptic Transmission / Q000235:genetics / Q000502:physiology
D002352:Carrier Proteins; D028044:Phosphate-Binding Proteins; D018698:Glutamic Acid