Aplysia pleural Ganglia 1 Hour After Long-Term Sensitization Training

We used a custom-designed microarray and qPCR to characterize the rapid transcriptional response to long-term sensitization training in the marine mollusk Aplysia californica. Aplysia were exposed to repeated noxious shocks to one side of the body (4 ten-second shocks at 90mA, 30 min ISI), a procedure known to induce a transcription-dependent and long-lasting increase in reflex responsiveness that is restricted to the side of training. One hour after training, pleural ganglia from the trained and untrained sides of the body were harvested; these ganglia contain the sensory nociceptors which help mediate the expression of long-term sensitization memory.  Microarray analysis from 8 biological replicates suggests that long-term sensitization training rapidly regulates at least 102 transcripts. We used qPCR to test a subset of these transcripts and found that 86% were confirmed in the same samples, and 83% of these were again confirmed in an independent sample (n = 9 animals). Thus, our new microarray design shows very strong convergent and predictive validity for analyzing the transcriptional correlates of memory in Aplysia. Fully validated transcripts include some previously identified as regulated in this paradigm (ApC/EBP and ApEgr) but also include novel findings. Specifically, we show that long-term sensitization training rapidly up-regulates the expression of transcripts which encode a C/EBP gamma, a glycine transporter, and a vacuolar-protein-sorting-associated protein. Within-subjects comparison of trained (Cy5) to untrained (Cy3) pleural ganglia with 8 biological replicates. Each replicate is a trained sample from two animals (right and left trained) and each untrained sample is from the same two aniamls (right and left untrained)