Napamezole hydrochloride is an orally active α-2 adrenergic receptor antagonist and serotonin ( 5-HT Receptor ) reuptake inhibitor, with K i values of 28 nM and 93 nM for rat α-2 and α-1 adrenergic receptors, respectively. Napamezole hydrochloride can be used for the research of depression [1] [2].
In Vivo, Napamezole (p.o.; s.c.) antagonizes clonidine-induced analgesia in mice, with an ED50 of 36 mg/kg via intragastric administration and 3 mg/kg via subcutaneous injection, indicating that it exhibits in vivo α2-adrenergic receptor blocking activity[1]. Napamezole (30 mg/kg; p.o.) enhances the conversion rate of norepinephrine in the rat brain, confirming its in vivo α-2 adrenergic receptor blocking activity[1]. Napamezole (≥ 1 mg/kg, i.v.) enhances the firing activity of locus coeruleus neurons in rats and reverses the inhibitory effect of Clonidine on this firing activity, indicating that it exhibits in vivo α2-adrenergic receptor blocking activity[1].
In Vitro, Napamezole (hydrochloride) inhibits [3H]Clonidine binding to rat brain alpha-2 adrenergic receptors with a Ki of 28 nM and inhibits [3H]Prazosin binding to rat brain alpha-1 adrenergic receptors with a Ki of 93 nM[2].
References:
[1]. Perrone MH, et al. In vivo assessment of napamezole, an alpha-2 adrenoceptor antagonist and monoamine re-uptake inhibitor. J Pharmacol Exp Ther. 1990;254(2):476-483.
[2]. Perrone MH, et al. Napamezole, an alpha-2 adrenergic receptor antagonist and monoamine uptake inhibitor in vitro. J Pharmacol Exp Ther. 1990;254(2):471-475.
In Vivo, Napamezole (p.o.; s.c.) antagonizes clonidine-induced analgesia in mice, with an ED50 of 36 mg/kg via intragastric administration and 3 mg/kg via subcutaneous injection, indicating that it exhibits in vivo α2-adrenergic receptor blocking activity[1]. Napamezole (30 mg/kg; p.o.) enhances the conversion rate of norepinephrine in the rat brain, confirming its in vivo α-2 adrenergic receptor blocking activity[1]. Napamezole (≥ 1 mg/kg, i.v.) enhances the firing activity of locus coeruleus neurons in rats and reverses the inhibitory effect of Clonidine on this firing activity, indicating that it exhibits in vivo α2-adrenergic receptor blocking activity[1].
In Vitro, Napamezole (hydrochloride) inhibits [3H]Clonidine binding to rat brain alpha-2 adrenergic receptors with a Ki of 28 nM and inhibits [3H]Prazosin binding to rat brain alpha-1 adrenergic receptors with a Ki of 93 nM[2].
References:
[1]. Perrone MH, et al. In vivo assessment of napamezole, an alpha-2 adrenoceptor antagonist and monoamine re-uptake inhibitor. J Pharmacol Exp Ther. 1990;254(2):476-483.
[2]. Perrone MH, et al. Napamezole, an alpha-2 adrenergic receptor antagonist and monoamine uptake inhibitor in vitro. J Pharmacol Exp Ther. 1990;254(2):471-475.