TABLE 2.Effect of XE991 on the shape of the evoked action potential (AP) in DA VTA neurons
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Control (7) | XE991, 1 µM (7) | Control (6) | XE991, 3 µM (6) | Control (7) | XE991, 10 µM (7) | |
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Amplitude, mV | 86.1 ± 2.0 | 87.0 ± 2.0 | 87.8 ± 2.1 | 88.7 ± 2.2 | 87.6 ± 1.2 | 87.2 ± 1.5 |
Half-width, ms | 1.3 ± 0.1 | 1.3 ± 0.1 | 1.1 ± 0.1 | 1.1 ± 0.1 | 1.2 ± 0.1 | 1.3 ± 0.1 |
Threshold, mV | –42.7 ± 0.9 | –42.8 ± 0.8 | –42.7 ± 1.0 | –42.4 ± 1.1 | –42.8 ± 1.2 | –42.9 ± 1.4 |
AHP-1, mV | 25.6 ± 1.5 | 24.0 ± 1.3* | 27.3 ± 1.9 | 25.1 ± 1.7** | 27.5 ± 1.1 | 22.5 ± 1.5** |
AHP-2, mV | 26.6 ± 2.8 | 26.6 ± 3.1 | 27.8 ± 3.8 | 28.6 ± 2.4 | 25.5 ± 4.1 | 24.4 ± 4.4 |
AHP-3, mV | 16.6 ± 1.0 | 15.7 ± 1.0* | 16.5 ± 1.5 | 14.8 ± 1.4* | 15.0 ± 1.2 | 11.2 ± 2.3** |
Values are means ± SE. Numbers of neurons (n) are in parentheses. AHP, spike afterhyperpolarization. All AP shape parameters were analyzed on the first AP evoked by a
10-pA depolarizing current injection (see Fig. 4, A1 and B). APs were evoked from the same membrane potential before and after XE991 treatment. DC current injection was used to keep
the membrane potential constant. Statistical significance was assessed with the paired Student's t-test. The asterisks indicate significant differences between values in control and in the presence of XE991 (
* P < 0.05;
** P < 0.01).