Aplysia Pleural Ganglia 7 Days After Long-Term Sensitization Training

We used a custom-designed microarray and qPCR to characterize the transcriptional response that persists 7 days after long-term sensitization training in the marine mollusk Aplysia californica, a time-point at which recall has decayed but savings memory is still possible to induce. Aplysia were exposed to a 1-day unilateral LTS training protocol (4 rounds of noxious shock at 30 min intervals, each shock 10s of 1/2s off 1/2on 90mA 60-hz biphasic square-wave shock). Training produced robust sensitization in all animals (measured as an increase in T-SWR response from baseline to 24h after training). One week (7 days) after training, animals were again post-tested, and showed little-to-no evidence of recall (average change from baseline = -4% on the trained side, -4% on the untrained side). Pleural ganglia were then harvested. Samples from a left-trained and right-trained animal were combined to smooth out lateralized gene expression. The pleural ganglia contains the VC nociceptors, which are thought to play a primary role in expressing LTS memory. Within-subjects comparison. Each array is a two-color approach hybridized to a matched trained and untrained set of samples (with each sample containing tissue from a left- and right-trained animal). Conducted with 8 biological replicates, meaning 8 arrays, each comparing paired trained and untrained samples.