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. Author manuscript; available in PMC: 2008 Nov 25.
Published in final edited form as: J Comp Neurol. 2004 Sep 27;477(4):386–398. doi: 10.1002/cne.20250

Fig. 3.

Fig. 3

VGLUT1-independent transmission arises from a distinct subpopulation of release sites made by a single cell. (A) The distribution of miniature EPSC (mEPSC) amplitudes recorded from stratum radiatum does not differ between mutant and wild-type mice (P > 0.1, Kolmogorov-Smirnov; wild type, n = 6; VGLUT1-/-, n = 5). (B) Mean mEPSC amplitude does not differ between knockout and wild-type animals. In contrast, the frequency of mEPSCs is severely reduced (*, P < 0.05; wild type, n = 6; VGLUT1-/-, n = 5). (C) In the presence of the use-dependent NMDA receptor antagonist MK-801, the decay rate of NMDA EPSCs from 9- to 10-day-old VGLUT1-/- slices does not differ from that of the wild type (P > 0.1). Decay curves could be fit by two exponentials, τ1 and τ2. The GABAB agonist baclofen (Bac) (60 μM) increases τ1, indicating its sensitivity to changes in probability of release (*, P < 0.01), whereas τ2 does not change under all conditions (P > 0.1; wild type, n = 7; VGLUT1-/-, n = 11; baclofen, n = 8). (D) Autaptic cultures prepared from newborn VGLUT1-/- hippocampi (10 to 14 days in culture) show reduced EPSC amplitudes relative to combined cultures of wild-type and VGLUT1+/- heterozygotes (P < 0.01; wild type/heterozygote, n = 26; VGLUT1-/-, n = 33). Autaptic IPSCs from knockout cultures were not significantly different from those of the wild type (P > 0.1; wild type/heterozygote, n = 31; VGLUT1-/-, n = 38). EPSC scale bar, 500 pA, 10 ms. IPSC scale bar, 1 nA, 50 ms. (E to J) Immunofluorescence for VGLUT1 (red) and VGLUT2 (green) in 8-day-old (8d) or adult (Ad) wild-type mouse CA1 hippocampus. (F) and (I) show high-magnification fields from the stratum radiatum (marked by the R) of (E) and (H), respectively. (G) and (J) show high-magnification fields of the corresponding stratum lacunosum moleculare (LM). VGLUT1 does not colocalize with VGLUT2 at either age. Fine puncta in stratum radiatum label for VGLUT2 (arrowheads) at 8 days (C) but not adulthood (I), whereas larger puncta in stratum lacunosum moleculare stain for VGLUT2 at both ages [(D) and (J)]. P, stratum pyramidale. Scale bar in (H), 60 μm [applies to (E) and (H)]; scale bar in (I), 4 μm [applies to (F), (G), (I), and (J)].