Fig. 2
Nrxn1+/− neurons display depressed ADBE. A-C) Hippocampal synaptosome lysates from either wild-type (WT) or Nrxn1+/− rats were probed for the presence of Neurexin-1 (Nrxn1, A) and total protein (B). (C) Quantification of Nrxn1 levels in both are displayed, normalised to total protein ± SEM, n = 3 independent synaptosome preparations for both WT and Nrxn1+/−, * p = 0.0365, unpaired t test. D-J) Hippocampal neurons derived from either WT or Nrxn1+/− rat embryos were transfected with synaptophysin-pHluorin (sypHy) after 7 days in vitro (DIV) and imaged at DIV 13–15. D, H) Mean sypHy fluorescence traces of WT and Nrxn1+/− hippocampal neurons normalised to either the total SV pool as revealed by NH4Cl (D) or peak fluorescence during electrical stimulation (H) ± SEM. E) Mean sypHy surface fraction presented as a percentage of the total SV pool ± SEM. F, G) Mean peak sypHy response in response to either 10 Hz (F) or 40 Hz (G) action potential trains ± SEM. (I, J) Mean sypHy retrieval time constants (t) in response to either 10 Hz (I) or 40 Hz (J) action potential trains ± SEM. For D-Jn = 9 coverslips for both WT and Nrxn1+/− from 3 independent cultures. (K, L) Primary hippocampal cultures derived either WT or Nrxn1+/− rat embryos were challenged with a train of action potentials (40 Hz, 10 s) in the presence of tetramethylrhodamine (TMR)-dextran (50 µM). TMR-dextran was immediately washed away and the number of TMR-dextran puncta were counted. (K) Representative images of TMR-dextran uptake in WT and Nrxn1+/− cultures. Scale bar = 50 μm. L) Mean number of TMR-dextran puncta per field of view normalised to WT ± SEM (n = 13 coverslips from 3 independent cultures for WT and Nrxn1+/−). (M) Primary hippocampal cultures derived from either WT or Nrxn1+/− rat embryos were fixed at DIV13-15 and stained for the presence of SV2A. (N) Mean number of SV2A puncta per field of view normalised to WT ± SEM (WT n = 12 coverslips, Nrxn1+/−n = 15 coverslips from 3 independent cultures). In all cases an unpaired two-sided students t test was performed, ** p = 0.0037, unpaired t test