Table 3.

Effect of age on isolated GnRH neurons

Property	Young	Middle aged	Old
Membrane properties
Capacitance	9.48 ± 0.27 pF	8.87 ± 0.37 pF	8.52 ± 0.43 pF
	n = 57	n = 31	n = 24
Input resistance	2.22 ± 0.14 GΩ	1.86 ± 0.18 GΩ	2.23 ± 0.25 GΩ
	n = 11	n = 7	n = 4
Action potential
Amplitude	123.3 ± 2.7 mV	115.4 ± 5.3 mV	115.6 ± 3.2 mV
	n = 13	n = 10	n = 13
Duration (at 1/2 amplitude)	1.56 ± 0.08 ms	1.60 ± 0.13 ms	1.55 ± 0.42 ms
		n = 10	n = 13
Spontaneous firing
Frequency	3.73 ± 0.31 Hza	2.79 ± 0.46 Hz	2.50 ± 0.35 Hz
	n = 28	n = 12	n = 14
Entropy	7.04 ± 0.07 bits	7.26 ± 0.11 bits	7.27 ± 0.10 bits
Mutual information	0.12 ± 0.02 bitsb	0.07 ± 0.03 bits	0.05 ± 0.03 bits
	n = 28	n = 12	n = 14
Depolarizing afterpotentials
3.5-msec pulse	5.32 ± 0.51 mV	3.57 ± 0.6 mV	4.09 ± 0.53 mV
	n = 14	n = 10	n = 14
200-msec pulse	8.12 ± 0.41 mVc	5.17 ± 0.62 mV	5.23 ± 0.59 mV
	n = 26	n = 12	n = 12

Age does not affect typical membrane measurements of health but does affect spontaneous firing and DAPs. 

^aSignificantly different from middle aged and old (P = 0.031, AVOVA on ranks). 

^bSignificantly different from middle aged and old (P = 0.046, Spearman correlation). 

^cSignificantly different from middle aged and old (P < 0.001, two-way ANOVA).