Meeting Abstract
P3.152 Sunday, Jan. 6 RNA-Seq analysis of sensory neurons from grasshopper mice: exploring the genetic basis for differential sensitivity to bark scorpion pain-inducing toxins in a scorpion predator DASKALANTONAKIS, D.*; CASSIDY, R.; BRUMLOW, C.; ROWE, M.; ROWE, A.; The Univ. of Texas, Austin; The Univ. of Texas, Austin; Sam Houston State Univ.; Sam Houston State Univ.; The Univ. of Texas, Austin ahrowe@utexas.edu
Pain is adaptive – warning of tissue damage. Because noxious stimuli produce short-term (escape) and long-term (avoidance) responses, many animals use painful venom to deter predators. The Texas striped bark scorpion [(TSB) (Centruroides vittatus)] produces the sensation of burning pain by injecting toxins that activate sensory neurons. Mearns’ grasshopper mice [(MG) (Onychomys arenicola)] attack, kill, and consume TSB scorpions. We measured the sensitivity of MG mice to TSB scorpion pain-inducing toxins by recording the duration of paw licking in mice whose hind paw had been injected with TSB venom; house mice (Mus) were used as a control. Mean paw licking scores for MG mice were significantly less than house mice, suggesting the former have evolved insensitivity to TSB’s pain-inducing toxins. Additionally, individual MG mice exhibited differential sensitivity to this scorpion’s painful toxins. While some mice were insensitive, others were highly so. These same MG mice, however, did not respond differentially to injections of another painful stimulus, formalin. These data suggest that individual variation in MG mice’s sensitivity to TSB pain-inducing toxins is specific to this scorpion’s toxins, and does not represent individual variability in each mouse’s threshold to pain. To determine the genetic basis for differential sensitivity to TSB pain-inducing toxins, we are sequencing mRNA (Illumina HiSeq) from the sensory neurons of low and high sensitivity MG mice. Analyses are focused on genes expressed in the pain pathway. Our goal is to identify differences between sensitivity phenotypes in the structure and expression of these genes.
