Table 2.

Effect of increasing concentrations of ketamine on properties of single action potentials (n=8)

	Overshoot (mV)	Duration (ms)	Max. positive slope (V s−1)	Max. negative slope (V s−1)
Control	47.5±3.0	1.6±0.1	124.1±8.6	−100.8±3.7
30 μM	35.2±2.6*	2.2±0.1	99.4±7.7*	−73.8±4.7**
100 μM	19.0±2.7***	3.4±0.3***	61.4±5.0***	−45.7±3.8***
300 μM	3.1±1.1***	5.1±0.3***	38.6±3.3***	−23.2±4.2***

Duration of action potentials is measured at the half-maximum amplitude {Madeja, 2000 7/id}. Positive and negative slope are the corresponding maximum values after differentiation of the action potentials. Significance levels are given as P<0.05 (^*), P<0.01 (^**) and P<0.001 (^***) for differences from control.