Table 2.

Correlations between mRNAs, and between mRNA and the learning index, in six regions of the hippocampal formation of 20 young and aged Long–Evans rats

Marker	βAPP	b-NOS	Mn-SOD	Cu/Zn-SOD
CA1 pyramidal cell layer
βAPP		0.48*	0.64**	0.62**
b-NOS			0.62**	0.32
Mn-SOD				0.44*
Learning index	0.54*	0.21	0.42	0.25

Marker	βAPP	b-NOS	Mn-SOD	Cu/Zn-SOD
CA2 pyramidal cell layer
βAPP		0.42	0.56**	0.39
b-NOS			0.31	0.39
Mn-SOD				0.46*
Learning index	0.56*	0.05	0.48*	0.38

Marker	βAPP	b-NOS	Mn-SOD	Cu/Zn-SOD
CA3 pyramidal cell layer
βAPP		0.51*	0.57**	0.43
b-NOS			0.53*	0.29
Mn-SOD				0.38
Learning index	0.44	0.11	0.21	0.32

Marker	βAPP	b-NOS	Mn-SOD	Cu/Zn-SOD
Hilus
βAPP		0.66**	0.59**	0.36
b-NOS			0.57**	0.15
Mn-SOD				0.36
Learning index	0.31	0.06	0.27	0.2

Marker	βAPP	b-NOS	Mn-SOD	Cu/Zn-SOD
Granule cells of the upper blade of the dentate gyrus
βAPP		0.76***	0.61**	0.32
b-NOS			0.71***	0.53*
Mn-SOD				0.59**
Learning index	0.52*	0.35	0.35	0.2

Marker	βAPP	b-NOS	Mn-SOD	Cu/Zn-SOD
Granule cells of the lower blade of the dentate gyrus
βAPP		0.81***	0.59**	0.54*
b-NOS			0.67**	0.54*
Mn-SOD				0.57**
Learning index	0.47*	0.45*	0.50*	0.24

Using calibrated film autoradiographs, the pyramidal and granule cell layers in the indicated regions of the dorsal hippocampal formation were repeatedly sampled (typically 8–10 for each subject). Linear regression was used to obtain the r values for correlations. Levels of significance: *p < 0.05; **p < 0.01; ***p < 0.001.