Figure 2.

Aging does not dramatically alter expression of excitatory, inhibitory, and purinergic signalling genes. Heatmaps show gene expression data presented as SD from mean expression for each gene across all ages (genes listed at bottom). Samples are grouped by age: young (top), middle age (middle), and old age (lower), with mean gene expression for each age group presented below. Dark values denote elevated expression (max = 4.5 SD above mean) and light values indicate reduced gene expression (min = −2.5 SD below mean). Grey cells denote sample failed QC. Genes with significantly altered expression across age highlighted by shading. (a) excitatory, inhibitory, and purinergic signalling genes are relatively stable in the dorsal spinal cord of the spinal cord across age, with the exception of the a2 glycine receptor subunit gene and two ATP sensitive ionotropic receptor genes (P2x1r and P2x4r). (b) expression of excitatory, inhibitory, and purinergic signalling genes were also generally stable in the ventral spinal cord of the spinal cord across age. Altered transcripts in this region all related to inhibitory signalling with the a2 glycine receptor subunit gene, α1 GABAA receptor subunit gene, and vesicular GABA transporter gene all reduced, along with a small decrease in expression of the gephyrin gene. (c) Schematics summarise genes that exhibited altered expression in middle (left) and old-age (right) versus young samples in the dorsal (red) and ventral spinal cord (blue).