Meeting Abstract

P2.76  Friday, Jan. 4  Characterization of Nociceptive Sensitization in Larval Manduca sexta MERCHASIN, Emily*; FUSE, Megumi; San Francisco State University; San Francisco State University emerchasin@gmail.com

Nociceptive sensitization occurs when a previously weak or neutral stimulus, such as a soft poke with a nylon filament, is able to evoke a defensive response following application of a noxious or painful stimulus such as a strong pinch. Sensitization of the defensive strike response, or nociceptive sensitization, in larval Manduca sexta has been demonstrated previously (Walters et al., 2001). The aim of the present study was to determine the degree in which nociceptive sensitization generalizes across abdominal segments in M. sexta, and what pathways were responsible for transmission of nociceptive information. Results from experiments on 5th instar larva, where a single noxious pinch was delivered to either the right or left proleg of abdominal segments 3, 4, 5 or 6 indicated that regardless of where the noxious stimulus was applied, nociceptive sensitization was induced, and the response was noted equally in all segments. That is, there was no difference in strike response among the abdominal segments tested. Additionally, the sides ipsilateral and contralateral to the site of noxious stimulation did not show significant differences in strike response when compared to other abdominal segments. Pharmacological studies further looked at the biochemical pathway for nociceptive transmission in M. sexta.