Kinetics of stimulation-evoked excitatory (EPSP, EPSC) and monosynaptic inhibitory responses (IPSP, IPSC, gGABAA)
| A. PSP/Cs | Dendrites (n= 9) | Somata (n= 7) |
|---|---|---|
| t(EPSP,onset) (ms) | 2.8 ± 0.5 | 2.9 ± 0.5 |
| t(IPSP,onset) (ms) | 2.8 ± 0.3 | 2.8 ± 0.6 |
| t(EPSC,onset) (ms) | 2.7 ± 0.3 | 3.0 ± 0.5 |
| t(IPSC,onset) (ms) | 3.1 ± 0.7 | 3.0 ± 0.3 |
| t(EPSP,peak) (ms) | 7.7 ± 0.5 | 7.6 ± 0.7 |
| t(IPSP,peak) (ms) | 16.7 ± 1.3* | 18.1 ± 1.9* |
| t(EPSC,peak) (ms) | 7.0 ± 0.6 | 7.1 ± 0.6 |
| t(IPSC,peak) (ms) | 11.2 ± 2.1*† | 13.3 ± 1.7*† |
| B. PSPs and gGABAA | Dendrites (n= 14) | Somata (n= 11) |
|---|---|---|
| gGABAA, rise time (ms) | 2.7 ± 0.4 | 2.9 ± 0.6 |
| IPSP, rise time (ms) | 5.7 ± 1.1* | 6.6 ± 0.8* |
| EPSP, rise time (ms) | 2.6 ± 0.5 | 2.7 ± 0.6 |
| t(peak,gGABA,A) (ms) | 6.1 ± 0.7 | 6.9 ± 0.9 |
| t(IPSP,peak) (ms) | 15.2 ± 2.1* | 18.3 ± 2.4* |
| t(EPSP,peak) (ms) | 7.0 ± 0.6 | 6.8 ± 0.8 |
| t(AP,peak) (ms) | 7.1 ± 1.4 (n= 3) | 7.0 ± 1.1 (n= 4) |
| C. gGABAA (% of peak) | Dendrites (n= 14) | Somata (n= 11) |
|---|---|---|
| Percentage of peak at t(IPSP,onset) | 15.8 ± 3.6 | 11.1 ± 2.3 |
| Percentage of peak at t(IPSP,peak) | 75.5 ± 8.4 | 70.5 ± 10.9 |
| Percentage of peak at t(EPSP,onset) | 13.8 ± 4.6 | 10.7 ± 3.7 |
| Percentage of peak at t(EPSP,peak) | 94.1 ± 5.5 | 91.9 ± 7.3 |
| Percentage of peak at t(AP,onset) | 94.5 ± 7.4 (n= 3) | 93.2 ± 9.4 (n= 4) |
| D. PSP/Cs and gGABAA | Dendrites (n= 7) | Somata (n= 4) |
|---|---|---|
| t(IPSP,peak) (ms) | 18.4 ± 3.6 | 20.4 ± 4.2 |
| t(IPSC,peak) (ms) | 12.3 ± 2.3* | 13.9 ± 3.3* |
| t(peak,gGABA,A) (ms) | 6.5 ± 0.9* | 7.1 ± 2.1* |
| t(EPSP,peak) (ms) | 6.1 ± 1.0 | 6.7 ± 1.5 |
| t(EPSC,peak) (ms) | 6.2 ± 0.8 | 6.5 ± 1.2 |
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A, kinetics of stimulation-evoked EPSPs, EPSCs, IPSPs and IPSCs recorded alternately in current-clamp and voltage-clamp mode in the same cells. In all comparisons, values of latencies to onset (EPSP, EPSC, IPSP, IPSC) were statistically identical in dendritic and somatic recordings (P > 0.05, ANOVA). B and C, kinetics of inhibitory conductances (gGABAA), EPSP and IPSP. B, comparison of rise time and latencies to peaks; C, percentage of the peak value of gGABAA at the time of denoted parameters. Peak gGABAA were 13.5 ± 4.6 nS (mean ± s.e.m. in 14 dendritic recordings) and 11.3 ± 3.6 nS (11 somatic recordings). D, latencies to peaks of gGABAA, IPSC, IPSP, EPSP and EPSC recorded in current clamp and discontinuous single-electrode voltage clamp in the same cells. In all recordings, respective orthodromic excitatory responses (EPSPs, EPSCs) were recorded first, respective inhibitory responses (IPSPs, IPSCs, gGABAA) following application of CNQX (20-100 μm), D-AP5 (40-100 μm) and saclofen (100 μM). The stimulation protocol (intensity adjusted to generate half-maximal EPSPs; 500 μm distance between recording and stimulation sites) was applied to elicit EPSP/EPSCs and IPSP/IPSCs, gGABAA. Data are depicted as means ± s.e.m. separated into recordings of somata and apical dendrites of CA1 pyramidal cells (n= number of recordings). t denotes the time of poststimulation latency measured from the onset of the stimulation artifact (see Fig. 2B). In all comparisons (A-D), kinetics of the same parameter showed no significant differences between dendritic and somatic recordings.
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↵* Significant difference between the inhibitory and excitatory parameter listed in the row above (e.g. t(IPSP,peak) and t(EPSP,peak))
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↵† significant difference between t(IPSC,peak) and t(IPSP,peak).