Table 2. Characteristics of spontaneous depolarizing potentials in spiny hilar neurons.
| Frequency of Events, Hz | ||||||||
|---|---|---|---|---|---|---|---|---|
| n | All events | 0–5 mV | 5–10 mV | 10–15 mV | 15–20 mV | 20–25 mV | 25–30 mV | |
| All cells | 58* | 40.2 ± 1.4 | 18.1 ± 1.1 | 10.7 ± 0.8 | 5.1 ± 0.6 | 3.1 ± 0.7 | 2.0 ± 0.6 | 0.8 ± 0.2 |
| Cells with excrescences | 9 | 38.5 ± 4.1 | 17.5 ± 2.1 | 8.9 ± 0.9 | 5.5 ± 1.0 | 3.4 ± 2.1 | 1.9 ± 0.9 | 0.9 ± 0.1 |
| Cells without excrescences | 13 | 39.4 ± 5.1 | 20.1 ± 1.5 | 10.0 ± 0.9 | 4.9 ± 0.8 | 2.8 ± 1.5 | 1.5 ± 0.5 | 1.0 ± 0.1 |
| Cells recorded with electrodes containing Lucifer yellow |
22 | 42.2 ± 4.3 | 22.2 ± 2.0 | 8.7 ± 1.0 | 5.9 ± 1.1 | 2.9 ± 0.9 | 2.0 ± 0.7 | 0.7 ± 0.1 |
| Cells recorded with electrodes containing potassium acetate |
−14* | 40.1 ± 3.9 | 17.9 ± 1.0 | 11.2 ± 0.8 | 4.8 ± 0.9 | 2.8 ± 1.9 | 2.2 ± 0.6 | 0.6 ± 0.2 |
| Cells perfused with 50 μM APV | 5 | |||||||
| Pre-APV | 41.0 ± 5.2 | 17.5 ± 4.0 | 12.4 ± 0.7 | 6.1 ± 0.9 | 3.0 ± 1.0 | 2.1 ± 0.8 | 0.9 ± 0.4 | |
| Post-APV | 39.7 ± 4.1 | 19.0 ± 3.7 | 11.1 ± 2.1 | 4.9 ± 0.7 | 3.7 ± 2.2 | 1.3 ± 0.9 | 1.2 ± 0.3 | |
| Cells perfused with low extracellular Mg2+ |
7 | |||||||
| Control (2 mM Mg2+) | 38.9 ± 3.7 | 19.2 ± 2.5 | 10.2 ± 1.5 | 5.5 ± 1.1 | 2.9 ± 0.9 | 1.0 ± 0.7 | 0.5 ± 0.1 | |
| Low Mg2+(l mM Mg2+) | 40.2 ± 5.1 | 20.0 ± 1.7 | 8.7 ± 2.1 | 5.6 ± 0.7 | 3.3 ± 1.2 | 1.6 ± 1.6 | 0.2 ± 0.2 | |
| Cells perfused with 25 μM bicuculline |
3 | |||||||
| Pre-bicuculline | 40.0 ± 3.5 | 19.6 ± 2.3 | 8.9 ± 1.1 | 6.3 ± 1.3 | 2.8 ± 0.8 | 1.9 ± 0.4 | 0.5 ± 0.2 | |
| Post-bicuculline | 41.8 ± 4.0 | 18.1 ± 1.9 | 11.2 ± 1.1 | 5.0 ± 1.0 | 3.0 ± 0.6 | 2.0 ± 0.3 | 0.7 ± 0.2 | |
| Cells perfused with 1 μM tctrodoloxin |
3 | |||||||
| Pre-tetrodotoxin | 39.2 ± 1.9 | 17.7 ± 1.1 | 9.2 ± 1.4 | 3.7 ± 0.8 | 2.0 ± 1.9 | 1.7 ± 1.2 | 1.0 ± 1.0 | |
| Post-tetrodotoxin | 38.9 ± 2.0 | 18.2 ± 2.2 | 9.6 ± 2.0 | 3.4 ± 1.4 | 1.5 ± 0.9 | 3.3 ± 1.2 | 2.0 ± 1.1 | |
All values except n values are means ± SE. APV, 2-amino-5-phosphonovaleric acid. For other abbreviations, see Table 1. Measurements of spontaneous events were made between −60 and −64 m V (see methods). Events of specific amplitudes were measured to the nearest half millivolt, so that “5-10 mV” contains events between 5.0 and 9.5 mV; 10–15 mV events include depolarizations between 5.0 and 9.5 mV, etc. Cells with excrescences were differentiated from cells without excrescences after Lucifer yellow dye injection (see methods). Pre-drug measurements were taken ≥5 min before drug application, and post-drug measurements were taken ≥15 min after switching perfusate from control buffer to buffer containing drug.
Does not include cells recorded during perfusion with 0–0.5 mM extracellular magnesium and 5 μM CNQX, cells examined with 25 μM bicuculline, or cells examined with tctrodotoxin.