Basic membrane properties of layer II pyramidal cells under different recording conditions
| NSR | Carbachol | BAPTA | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Vm | Rin | A.P. amp. | Vm | Rin | A.P. amp. | Vm | Rin | A.P. amp. | |
| Naive | −84.5 ± 4.5 | 38.0 ± 9.4 | 101.3 ± 4.7 | −79.8 ± 3.4 | 43.6 ± 6.6 | 100.9 ± 4.3 | −79.9 ± 4.3 | 30.9 ± 9.1 | 103.0 ± 5.7 |
| n = 29 (10) | n = 23 (10) | n = 29 (10) | n = 7 (3) | n = 6 (3) | n = 8 (3) | n = 22 (5) | n = 17 (5) | n = 19 (5) | |
| Trained | −82.4 ± 2.9 | 37.2 ± 9.2 | 101.1 ± 5.9 | −82.0 ± 3.9 | 37.0 ± 7.2 | 100.5 ± 6.3 | −79.4 ± 3.9 | 32.6 ± 7.4 | 101.0 ± 6.2 |
| n = 27 (9) | n = 20 (9) | n = 26 (9) | n = 18 (7) | n = 13 (7) | n = 15 (7) | n = 20 (5) | n = 19 (5) | n = 19 (5) | |
| Pseudo- | −84.4 ± 3.8 | 37.4 ± 8.9 | 103.3 ± 4.1 | −81.2 ± 3.2 | 41.1 ± 14.5 | 102.0 ± 5.1 | −81.4 ± 3.5 | 34.4 ± 10.0 | 100.0 ± 5.2 |
| trained | n = 39 (11) | n = 32 (11) | n = 38 (11) | n = 18 (7) | n = 15 (7) | n = 19 (7) | n = 22 (4) | n = 20 (5) | n = 21 (5) |
Membrane resting potential (Vm) was determined from the voltage change accompanying electrode withdrawal from the cell at the end of the recording. Input resistance (Rin) was determined by calculating the best linear regression fit to a voltage–current curve, constructed from voltage responses to 100 msec current pulses ranging between −0.3 and +0.3 nA. Action potential amplitude was measured from the resting potential to the peak. Basic membrane properties in cells from naive, pseudotrained, and trained rats were similar to each other when recorded in normal saline Ringer's solution. Carbachol affectedVm and Rin in neurons from pseudotrained and naive rats, but not in cells from trained rats. With BAPTA in the recording electrode, Rin was somewhat decreased in all groups. Values represent mean ± SD.n = number of cells, the number of rats is noted in brackets. NSR, Normal saline Ringer's solution.