Table 3.

Passive and active membrane properties of juvenile and adult PV interneurons expressing, not expressing, or exogenously expressing SAP97

	Juvenile		Adult
	SAP97⁺	SAP97⁻	SAP97⁺	SAP97⁻	SAP97egfp
Firing pattern
Delay first AP (ms)	440 ± 80	500 ± 80	510 ± 170	360 ± 90	276 ± 125
ISI average (ms)	28.9 ± 1.2	29.5 ± 1.5	26.9 ± 2.6	27.1 ± 2.2	26.1 ± 3.0
Frequency adaptation	0.96 ± 0.20	1.12 ± 0.12	1.42 ± 0.23	1.27 ± 0.11	0.72 ± 0.24
Max ISI (ms)	144 ± 35^*	62 ± 10	308 ± 118^*	53 ± 9	208 ± 46^**
Min ISI (ms)	18.2 ± 1.5^*	23.0 ± 1.7	15.5 ± 1.1^*	19.4 ± 1.7	12.3 ± 1.3^**
Max/Min ISI	9.2 ± 2.6^*	2.8 ± 0.5	20.2 ± 7.4^*	3.1 ± 0.8	17.4 ± 3.6^**
CV frequency	0.22 ± 0.04	0.17 ± 0.03	0.24 ± 0.03	0.20 ± 0.04	0.28 ± 0.02^*
F/I slope (Hz/pA)	1.8 ± 0.3^*	2.6 ± 0.4	0.9 ± 0.05^*^$	1.2^$ ± 0.15	1.01 ± 0.11
Passive
V_m (mV)	−85 ± 1.8^*	−90 ± 1.7	−85 ± 1.7	−88 ± 1.5	−86 ± 2.0
R_m (MΩ)	88 ± 9.7^**	130 ± 13	118 ± 13^**^$	173 ± 14^$	110 ± 15^**
Rheobase (pA)	450 ± 66^*	290 ± 40	270 ± 10^*^$	215 ± 20	346 ± 62^*
AP shape
AP threshold (mV)	−45.6 ± 2.5	−47.3 ± 1.2	−49.3 ± 1.6	−49.7 ± 1.5	−53.4 ± 2.1
AP 10–90% rise (ms)	0.25 ± 0.01	0.29 ± 0.01	0.21 ± 0.01^*	0.26 ± 0.02	0.20 ± 0.01^**
AP half-width (ms)	0.48 ± 0.02^*	0.63 ± 0.08	0.37 ± 0.02^*^$	0.46 ± 0.04^$	0.32 ± 0.01^***
AHP peak (mV)	−25.3 ± 0.6	−23.9 ± 1.0	−24.5 ± 1.5	−23.6 ± 1.0	−23.6 ± 1.5
AHP latency (ms)	1.7 ± 0.1	3.0 ± 0.9	1.1 ± 0.1^*^$	1.5 ± 0.2	0.8 ± 0.04^**
AHP area (V/s)	−210 ± 20^**	−420 ± 70	−140 ± 10^***^$	−239 ± 15^$	−137 ± 10^***
Number of interneurons	8	6	5	15	8

↵Juvenile (P15–P17) or adult (P56–P65) PV interneurons are characterized by firing pattern, passive membrane properties, and AP shape (see Materials and Methods). Values shown as mean ± SEM. A t test was used to determine whether the value for SAP97⁺ or SAP97egfp were significantly different from that for SAP97⁻ within the same age (*p < 0.05, **p < 0.01, and ***p < 0.001) or between different ages within SAP97⁻ or SAP97⁺ (^$p < 0.05).