ICI 174864

ICI 174864 is a selective and brain-penetrant δ-opioid receptor antagonist with K_e values of 22.0 nM to 30.6 nM at δ-opioid receptor in mouse vas deferens. ICI 174864 selectively blocks biological effects mediated by the δ-opioid receptor agonist DPDPE (HY-P1334) after central administration. ICI 174864 reverses hypotension in rats with endotoxic shock and inhibits acetic acid-induced writhing in mice. ICI 174864 can be used for the research of opioid receptor subtypes, endotoxic hypotension and analgesic pathways^{[1][2][3][4][5]}. In Vitro:ICI 174864 selectively antagonizes delta opioid receptors in in vitro biochemical systems^[2]. In Vivo:ICI 174864 (1-100 μg; i.c.v.; single dose) acts as a selective, reversible central δ-opioid receptor antagonist at 3 μg with no effect on μ-opioid receptor-mediated activity, but exhibits non-Naloxone (HY-17417A)-reversible agonistic effects at doses ≥6 μg^[1].
ICI 174864 (10 μg; i.c.v.; single dose; 3-10 mg/kg; s.c.; single dose) induces dose-dependent behavioral depression and ptosis via s.c. administration, and postural abnormalities, barrel rotation, and hypothermia via i.c.v. administration in naive male Sprague Dawley rats^[2].
ICI 174864 (10 μg; i.c.v.; single dose) suppresses acetic acid-induced writhing in male albino mice in a Naloxone-sensitive manner, while 5 μg (i.c.v.; single dose) selectively antagonizes the writhing-suppressant effect of delta agonist DPDPE (HY-P1334) without affecting mu agonist DAGO^[2].
ICI 174864 (3μg; i.c.v.; single dose) completely blocks DADL-induced hyperphagia^[3].
ICI 174864 (3 mg/kg; i.v.; single dose) significantly reverses endotoxic shock hypotension in male Sprague Dawley rats, without affecting blood pressure in normotensive rats^[5].
ICI 174864 (3 mg/kg; i.v.; single dose) produces only a rapid, transient pressor response with no sustained effect in normotensive male Sprague Dawley rats^[5].