Biochemical effects of the antidepressant paroxetine, a specific 5-hydroxytryptamine uptake inhibitor.

Article Details

Citation

Copy to clipboard

Thomas DR, Nelson DR, Johnson AM

Biochemical effects of the antidepressant paroxetine, a specific 5-hydroxytryptamine uptake inhibitor.

Psychopharmacology (Berl). 1987;93(2):193-200. doi: 10.1007/bf00179933.

PubMed ID

2962217 [ View in PubMed

]

Abstract

Paroxetine was shown to be a potent (Ki = 1.1 nM) and specific inhibitor of [3H]-5-hydroxytryptamine (5-HT) uptake into rat cortical and hypothalamic synaptosomes in vitro. Lineweaver-Burk kinetic analysis determined that this inhibition was competitive in nature, implying a direct interaction with the 5-HT uptake transporter complex. Oral administration of paroxetine produced a dose-related inhibition of [3H]-5-HT uptake (ED50 = 1.9 mg/kg) into rat hypothalamic synaptosomes ex vivo with little effect on [3H]-l-noradrenaline (NA) uptake (ED50 greater than 30 mg/kg). This selectivity for 5-HT uptake was maintained after oral dosing for 14 days. Paroxetine (ED50 1-3 mg/kg PO) prevented the 5-HT depleting effect of p-chloroamphetamine (PCA) in rat brain, demonstrating 5-HT uptake blockade in vivo. Radioligand binding techniques in rat brain in vitro showed that paroxetine has little affinity for alpha 1, alpha 2 or beta adrenoceptors, dopamine (D2), 5-HT1, 5-HT2 or histamine (H1) receptors at concentrations below 1000 nM. Paroxetine demonstrated weak affinity for muscarinic receptors (Ki = 89 nM) but was at least 15 fold weaker than amitriptyline (Ki = 5.1 nM). Paroxetine, therefore, provides a useful pharmacological tool for investigating 5-HT systems and furthermore should be an antidepressant with reduced tricyclic-like side-effects.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Paroxetine	Alpha-1 adrenergic receptors (Protein Group)	Protein group	Humans	Unknown	Binder	Details
Paroxetine	Alpha-2 adrenergic receptors (Protein Group)	Protein group	Humans	Unknown	Binder	Details