Figure 2: Training-induced upregulation of GluA1 AMPA receptors during memory consolidation in Lymnaea.

(a) A representative example of GluA1 immunoblot bands from a paired, an unpaired and a naive sample, run on the same gel, is shown above the graphs (full-length blot is presented in Supplementary Fig. 7a). Density data obtained from paired (N=8) and unpaired (N=8) samples were normalized to the mean of the density data obtained from naive samples ran on the same gels (N=8), which provided a baseline level of 1 (dashed line). In the graphs means±s.e.m. are shown. Both paired and unpaired training results in significantly increased GluA1 receptor protein levels in the ‘learning’ ganglia at 6 h post training (one-sample t-tests: paired versus naive baseline, P=0.047; unpaired versus naive baseline, P=0.048). There is no statistically significant difference between the GluA1 levels in the samples from the paired and unpaired group (two-tailed unpaired t-test: paired versus unpaired group, P=0.71). Asterisks indicate significant (at least P<0.05) differences compared with the naive baseline. (b) At 24 h post training, only the paired group (N=19) showed a conditioned response to the CS. Means±s.e.m. of the feeding response to the CS are shown. Naive animals (N=22) or animals subjected to unpaired training (CS-US interval 1 h, N=20) did not respond to the CS (ANOVA, P=0.0001. Tukey’s test: paired versus unpaired, P<0.05, paired versus naive, P<0.05, unpaired versus naive, P>0.05). Asterisk indicates significance compared with both unpaired and naive response levels. These experiments were replicated twice.