In this study, we focused on a subset of signaling systems which were well represented in the available data. We divided up the 130 assayed genes into families based on the signaling systems in which they participate. In most cases these were sets of receptors for a particular signaling molecule, which annotations were provided with the chip; the genes for CRH were selected by DK who has specialized expertise. This process yielded seven gene sets which had at least four member genes; several other signaling systems (e.g. opioids) had fewer than four genes represented on the chip; these were not considered further for a systems-analysis approach. We concentrated on those seven, which included receptors and other molecules involved in neurotransmission via norepinephrine, acetylcholine, dopamine, CRH, gamma-amino butyric acid (GABA), glutamate, and serotonin. The genes in each group were as comprehensive as possible limited only by the coverage on the chip. The genes in the gene sets are shown in Table 1.
