Dopamine is the main catecholamine in the central nervous system. The dopamine D4 receptor is abundantly expressed in the cortex and hypothalamus, and plays a key role in the regulation of sexual function in mammals. ABT-724 is a highly potent, selective dopamine D4 receptor with an EC50 value of 12.4nM and 61% efficacy for human dopamine D4 receptor, but shows no effect on dopamine D1, D2, D3, or D5 receptors. ABT-724 also exhibits potent but partial agonist effects on rat and ferret D4 receptors with EC50 values of 14.3±0.6nM and 23.2±1.3nM, respectively. Subcutaneous injection of ABT-724 at doses of 0.01, 0.03, 0.1, 0.3, and 1μmol/kg induced significant facilitation of penile erection in rats. The maximal effect was observed at 0.03μmol/kg with a 77% incidence, compared to 23% incidence in the control group. The latency to induce a penile erection in ABT-724-treated rats was 18.7 minutes. Also in rats with chronically implanted cannulas, injection of ABT-724 directly into the lateral ventricle significantly facilitated erectile responses at 3nmol. Subcutaneous administration of ABT-724 at 0.0025μmol/kg resulted in 2.0±0.6 episodes of increase in intracavernous pressure in an awake freely moving rat.[1]
作用机制
ABT-724 is a selective dopamine D4 receptor agonist that facilitates penile erection in rats without affecting cardiovascular, gastrointestinal, or central nervous system function.[1]
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