BRL 54443

BRL 54443 is a potent 5-HT_1E/1F receptor agonist (K_i values are 1.1 nM and 0.7 nM respectively); displays > 30-fold selectivity over other 5-HT and dopamine receptors^[1]. In Vitro: Despite its low affinity for other receptors [5-HT_1A (63 nM), 5-HT_1B (126 nM), 5-HT_1D (63 nM), 5-HT_2A (1259 nM), 5-HT_2B (100 nM), 5-HT_2C (316 nM), 5-HT₆ (>10,000 nM), 5-HT₇ (>10,000 nM), D₂ (501 nM), D₃ (631 nM), and α_1B-adrenoceptors (1259 nM)], BRL54443 binds with high affinity at 5-HT_1F receptors^[1].
In DG membranes, BRL54443 selectively stimulates 5-HT_1E receptors and potently inhibits forskolin-dependent cAMP production (IC₅₀=14 nM). BRL 54443 also induces contraction (-log EC₅₀=6.52)^[2].
In Vivo: Reduction of flinching was considered as antinociception. Ipsilateral, but not contralateral, peripheral administration of BRL54443 (5-HT(1E/1F); 3-300 microg/paw) significantly reduced formalin-induced flinching in rats^[3].