TABLE 3.Comparisons of the characteristics of the in vitro bursts of SON OT neurons with the bursting firing of VP neurons in hypothalamic slices from lactating rats
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| Spikes in the In Vitro B |
In vitro B |
Depolarization during B |
AHP |
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| Amplitude, mV |
50% Amplitude Width, ms |
FR of B, Hz |
Duration of B, s |
Peak FR, Hz |
Latency to PF, s |
Post-B Silence, s |
Level, mV‡ |
Length, s |
Amplitude, -mV |
50% Amplitude Width, ms |
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| Bursts | ||||||||||||||||||
| OT neurons (n = 27) | ||||||||||||||||||
| 0-4 s before | 61.2 ± 1.3 | 2.2 ± 0.1 | 3.5 ± 0.5 | 4 | 12.2 ± 1.3 | 2.4 ± 0.2 | 0 | 7.1 ± 0.5 | 44.5 ± 3.3 | |||||||||
| During | 57.8 ± 1.4a | 2.7 ± 0.1b | 14.7 ± 1.4b | 3.3 ± 0.3 | 40.4 ± 7.4b | 0.27 ± 0.04b | 1.8 ± 0.5 | 4.0 ± 0.3b | 1.0 ± 0.1 | 7.6 ± 0.4 | 29.0 ± 1.8b | |||||||
| 0-4 s after | 60.9 ± 1.3 | 2.3 ± 0.1 | 4.2 ± 0.7 | 4 | 11.0 ± 1.5 | 2.2 ± 0.2 | 0.9 ± 0.4b | 7.1 ± 0.5 | 42.9 ± 3.4 | |||||||||
| VP neurons (n = 5) | ||||||||||||||||||
| 0-4 s before | 64.5 ± 1.6c | 2.0 ± 0.3 | 4.4 ± 1.2 | 4 | 12.8 ± 2.4 | 3.2 ± 0.2 | 1.5 ± 0.4 | 9.7 ± 2.2 | 29.6 ± 2.9d | |||||||||
| During | 63.0 ± 2.3c | 2.3 ± 0.3c | 14.1 ± 2.9b | 5.5 ± 0.6d | 46.5 ± 15.0 | 0.14 ± 0.04b,c | 0.68 ± 0.41c | 2.8 ± 0.5a,c | 1.4 ± 0.5 | 9.1 ± 1.3 | 23.5 ± 3.6c | |||||||
| 0-4 s after | 63.5 ± 1.9 | 2.2 ± 0.3 | 8.1 ± 2.7c | 4 | 14.1 ± 4.8 | 2.4 ± 0.4 | 1.3 ± 0.3 | 9.3 ± 1.8 | 22.5 ± 2.1a,d | |||||||||
| Short phasic burst (n = 34) | ||||||||||||||||||
| During | 59.3 ± 1.3e | 2.3 ± 0.1d | 10.1 ± 0.8c,e | 3.5 ± 0.2f | 35.5 ± 15.8 | 1.21 ± 0.19d,f | 3.3 ± 0.7d,f | 6.9 ± 0.8d,f | 3.5 ± 0.2d,f | 8.0 ± 0.4 | 31.3 ± 2.0f | |||||||
| Portions of the bursts | ||||||||||||||||||
| OT neurons (n = 27) | ||||||||||||||||||
| Initiation | 59.6 ± 1.4 | 2.2 ± 0.1 | 21.6 ± 2.8 | 1.7 ± 0.5 | 6.6 ± 0.4 | 27.5 ± 2.6 | ||||||||||||
| Peak | 55.3 ± 1.6a | 2.5 ± 0.2b | 28.5 ± 3.0a | 5.0 ± 0.5b | 0.5 ± 0.07 | 8.3 ± 0.4b | 22.5 ± 1.7a | |||||||||||
| End | 60.1 ± 1.3 | 2.6 ± 0.2b | 8.4 ± 0.8b | 1.7 ± 0.3 | 7.4 ± 0.4a | 40.7 ± 3.1b | ||||||||||||
| VP neurons (n = 5) | ||||||||||||||||||
| Initiation | 63.6 ± 1.3c | 2.0 ± 0.3 | 23.1 ± 2.5 | 2.8 ± 0.5c | 8.5 ± 1.2d | 20.7 ± 2.9c | ||||||||||||
| Peak | 60.6 ± 2.9c | 2.1 ± 0.3 | 27.3 ± 2.9 | 3.5 ± 0.4a,c | 0.9 ± 0.2d | 9.7 ± 0.8c | 20.4 ± 4.0 | |||||||||||
| End |
62.7 ± 2.4 |
2.3 ± 0.3 |
10.8 ± 1.6 |
2.0 ± 0.6 |
9.3 ± 1.8 |
27.3 ± 6.5c |
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The level of depolarization during B (‡) was measured at 80% of the peak depolarization and compared with 1 min before the
burst. VP, vasopressin. a P < 0.05 and b P < 0.01 compared with control (before burst or initiation of burst) by paired t-test; c P < 0.05 and d P < 0.01 compared with the bursts of OT neurons by Student's t-test; e P < 0.05 and f P < 0.01 compared with that during the bursts of VP neurons by Student's t-test.