CIRAZOLINE HYDROCHLORIDE

Cirazoline is an α₁-adrenergic receptor (α₁-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 (EC₅₀s = 70.7, 79.4, and 239.8 nM, respectively). It also acts as an antagonist at α₂-ARs with a pA₂ 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.

Cirazoline hydrochloride has been used to activate the α1-noradrenergic receptors and to study the inhibitory effect of neurokinin1 (NK1) antagonists on respiratory activity using the brainstem transverse slice.

Selective α 1 agonist. Also available as part of the α 1 -Adrenoceptor Tocriset™ and Mixed Adrenergic Tocriset™ .

Cirazoline is a selective α1-adrenoceptor agonist and also a non-selective ligand for the imidazoline binding site. Cirazoline dereases spatial working memory performance in aged monkeys.

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