Description
Ciproxifan is a histamine H
3 receptor antagonist (K
i = 0.5 nM for inhibition of histamine release in rat synaptosomal preparations). It is selective for histamine H
3 over histamine H
1 and H
2, M
3 muscarinic, and α
1D- and β
1-adrenergic receptors (K
is = 3.15-25 μM), as well as the serotonin (5-HT) receptor subtypes 5-HT
1B, 5-HT
2A, 5-HT
3, and 5-HT
4 (K
is = 1.58-15 μM) in radioligand binding assays. Ciproxifan (3-300 nM) inhibits relaxation in precontracted isolated guinea pig ileal longitudinal muscle induced by R-(–)-α-methylhistamine .
In vivo, ciproxifan reduces R-(–)-α-methylhistamine-induced water consumption in rats (ED
50 = 0.09 mg/kg). It increases wake episode duration and latency to fall asleep in rats when administered at a dose of 2 mg/kg.
