FIGURE 5.

Human brain-derived cells display predominantly β₂-AR activity. (A) Functional cAMP responses to a panel of β-AR agonists in primary human hippocampal astrocytes, a representative concentration–response curve from examination of several types of brain-derived human primary cells and cell lines. Representative curves are displayed, each with four technical replicates, showing mean ± SEM cAMP HTRF responses normalized to the full agonist isoprenaline. (B) The human brain cells tested have agonist fingerprints like those of recombinant CHO-K1/β₂-AR cells, suggestive of predominantly β₂-AR endogenous function. (C) Similarity of each agonist fingerprint to the CHO-K1/β₂-AR system by summing the squares of differences for each agonist Δlog(E_max/EC₅₀) value.