Figure 1.
Altered NLG1 surface membrane levels upon application of chemical treatment designed to induce LTP or LTD, respectively. A, B, Chemical treatment designed to induce LTP significantly increases NLG1/3 at neuronal surface membranes. A, Surface biotinylation analysis of acute hippocampal slices detected against NLG1 and pan-cadherin (loading control). B, Neuronal surface biotinylation analysis of NLG1/3 and pan-cadherin (loading control) in cultured hippocampal neurons. C, D, Chemical treatment designed to induce LTD significantly reduces NLG1/3 from neuronal surface membranes. C, Surface biotinylation analysis of acute hippocampal slices detected against NLG1 and pan-cadherin (loading control). D, Neuronal surface biotinylation analysis of NLG1/3 and pan-cadherin (loading control) in cultured hippocampal neurons. Values reflect relative Western blot signal intensities of surface membrane NLG1/3 protein levels, analyzed using the ImageJ software. Error bars represent the SEM. *p < 0.05; **p < 0.01. E, F, Chemical LTP or chemical LTD induction in acute slices of P30 C57BL/6N mice causes a long-lasting increase or depression of fEPSPs, respectively. E, Chemical LTP induction by treatment with forskolin and rolipram led to a long-term increase of fEPSPs by 30% (average of the normalized fEPSP slopes in the last 5 min of recording: 1.29 ± 0.05, n = 5). F, Chemical LTD induction by DHPG treatment caused long-term depression of fEPSPs by 32% (average of the normalized fEPSP slopes in the last 5 min of recording: 0.76 ± 0.03, n = 4). G, Examples showing recordings of spontaneous mEPSCs from a control cultured hippocampal neuron (upper panel) and a cultured neuron treated with forskolin/rolipram (lower panel). H, Mean ± SEM of interevent intervals of control (DMSO treatment) and forskolin/rolipram-treated neurons; the graph shows a very significant difference between the two means (control: 1041.12 ± 216.29 ms, n = 9; forskolin/rolipram: 321.22 ± 65.63 ms, n = 11; p < 0.01). Forskolin/rolipram treatment induces a drastic increase in synaptic activity. The mean values of mEPSC amplitudes of the two groups of neurons were slightly different; however, this difference was not statistically significant (control: 14.4 ± 1.2 pA; forskolin/rolipram: 17.0 ± 2.0 pA; p = 0.296). Error bars represent the SEM. **p < 0.01.