P1.187 Saturday, Jan. 4 15:30 Thermal nociception in Louisiana red swamp crayfish (Procambarus clarkii) PURI, S; FAULKES, Z*; The University of Texas-Pan American; The University of Texas-Pan American email@example.com
Nociceptors are neurons tuned to tissue damage. Many invertebrate taxa, including insects, have nociceptors, but there is no clear evidence for nociceptors in crustaceans. We examined the behavioural responses of crayfish (Procambarus clarkii) to extreme high (>45°C) and low (<5°C) temperatures, which are normally considered noxious to other organisms. Crayfish reacted more strongly to the touch of high temperatures compared to room temperature controls, but did not differ in their response to low temperatures compared to controls, providing evidence of nociceptive behaviour. We then tested the physiological responses of sensory neurons in the antenna using extracellular recording. Small amounts of water of different temperatures were applied to isolated antennae in vitro. Preliminary data suggest that high temperatures frequently cause an increased neural response compared to controls, while low temperatures rarely differ from room temperature controls. There do not appear to be neurons that fire only in response to noxious stimuli; instead, neurons fire at an increased rate to noxious stimuli. These combined behavioural and physiological data are consistent with the hypothesis that crayfish have polymodal sensory neurons that act as nociceptors, not merely thermoreceptors.