Table 1.

Tat-mediated increase in neuronal excitability is Tat specific and long lasting^a

	Cells with multiple APs/N	Em (mV)	Rheobase (pA)	AP threshold (mV)	AP height
Control	6/19	−50.6 ± 1.5	20 ± 5	−11.5 ± 2.7	77.7 ± 5.8
100 nm Tat	19/20*	−49.2 ± 1.2	10 ± 2*	−16.1 ± 1.2*	87.9 ± 3.8*
Inactivated 100 nm Tat	1/5	−50.2 ± 1.4	20 ± 6	−13.2 ± 1.4	71.7 ± 8.7
Tat−	1/10	−48.9 ± 4.6	24 ± 3	−16.3 ± 1.3	51.9 ± 3.7
Tat+	11/11*	−52.5 ± 1.0	10 ± 0*	−21.0 ± 0.8*	71.8 ± 2.4*

^aWhole-cell patch-clamp experiments in current-clamp mode on neurons pretreated with 100 nm Tat for 17 to 48 h. These neurons fired a statistically significant higher number of multiple action potentials and at lower rheobase and action potential thresholds compared with controls. Neurons treated with heat-inactivated Tat were less excitable compared with Tat pretreated and as excitable as controls (untreated neurons). Neurons isolated from Tat⁺ mice were also more excitable than Tat⁻ mice neurons.

*p < 0.05 (paired t test).