Description
Cirazoline is an α
1-adrenergic receptor (α
1-AR) agonist (K
is = 120, 960, and 660 nM for recombinant α
1A-, α
1B-, and α
1D-ARs, respectively, in CHO cell membranes). It acts as a full agonist at α
1A- and a partial agonist at α
1B- and α
1D-ARs
in vitro (EC
50s = 70.7, 79.4, and 239.8 nM, respectively). It also acts as an antagonist at α
2-ARs with a pA
2 value of 7.56 to inhibit the norepinephrine-induced twitch response in isolated pig ileum. Cirazoline (0.01-1 μg/kg) decreases blood pressure when administered
via microinjection to the nucleus reticularis lateralis (NRL) of anesthetized normotensive cats. It enhances spatial memory and reduces depressive- and anxiety-like behavior in mice when administered at a concentration of 10 mg/L in drinking water for 2-9 months. It also enhances performance in the variable delayed response task in aged rhesus monkeys at high doses of 1-10 μg/kg but impairs performance at lower doses of 0.01-1 μg/kg.
