Cirazoline is a full

agonist An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the ago ...

at the α_1A adrenergic receptor, a

partial agonist In pharmacology, partial agonists are drugs that bind to and activate a given receptor, but have only partial efficacy at the receptor relative to a full agonist. They may also be considered ligands which display both agonistic and antagonistic e ...

at both the α_1B and α_1D adrenergic receptors, and a nonselective

antagonist An antagonist is a character in a story who is presented as the chief foe of the protagonist. Etymology The English word antagonist comes from the Greek ἀνταγωνιστής – ''antagonistēs'', "opponent, competitor, villain, enemy, riv ...

to the α₂ adrenergic receptor. It is believed that this combination of properties could make cirazoline an effective

vasoconstricting Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vessel ...

agent. Cirazoline has also been shown to decrease food intake in rats, purportedly through activation of α₁ adrenoceptors in the

paraventricular nucleus The paraventricular nucleus (PVN, PVA, or PVH) is a nucleus in the hypothalamus. Anatomically, it is adjacent to the third ventricle and many of its neurons project to the posterior pituitary. These projecting neurons secrete oxytocin and a smaller ...

in the hypothalamus of the brain.Administration of cirazoline also seemed to present impairment in the spatial memory of monkeys through the activation of the same receptors that showed decreased food intake in rats.However in preliminary studies, through stimulation of α₂ adrenoceptors, working memory is comparatively improved.

References

Alpha-1 adrenergic receptor agonists Alpha-2 blockers Cyclopropyl compounds Imidazolines Phenol ethers {{biochem-stub