Related Experiment Video
Updated: Aug 20, 2026

Methods for the Discovery of Novel Compounds Modulating a Gamma-Aminobutyric Acid Receptor Type A Neurotransmission
Published on: August 16, 2018
Neuropharmacology of the anxiolytic drug opipramol, a sigma site ligand
W E Müller1, B Siebert, G Holoubek
1Department of Pharmacology, Biocenter University Frankfurt, Marie-Curie-Strasse 9, D-60439 Frankfurt, Germany. pharmacolnat@em.uni-frankfurt.de
Abstract:
Although opipramol is structurally related to imipramine, it does not represent a tricyclic antidepressant drug as it does not inhibit the neuronal uptake of norepinephrine and/or serotonin. Unlike imipramine it is a rather potent sigma ligand with modest subclass selectivity which is similar in vitro as well as ex vivo. Opipramol is active in several behavioural paradigms indicative of anxiolytic properties at doses (1-10 mg/kg), which are also needed to occupy sigma binding sites. Somewhat higher doses (10-20 mg/kg) are needed for "antidepressant like" effects. The data allow the conclusion that interaction with sigma sites is involved in the anxiolytic and antidepressant effects of opipramol albeit a contribution of its weaker D (2)-antagonistic and 5-HT2-antagonistic properties cannot be totally be excluded.
Related Concept Videos
Opioid Receptors: Overview
Ligand-Gated Ion Channel Receptor: Gating Mechanism
Anxiolytic Drugs: Overview
Primary Types of Anxiolytic Drugs
1. Benzodiazepines:
Benzodiazepines bind to the GABA-A receptor in the brain, enhancing GABA's interaction. This action reduces neurotransmission, effectively blocking anxiety-associated limbic circuitry.
Drug-Receptor Interaction: Agonist
Agonists can bind to receptors in different ways. Some agonists bind directly to the receptor's active site, mimicking the endogenous ligand's action.
Sedatives and Hypnotics Drugs: Miscellaneous Agents
Melatonin congeners like ramelteon (Rozerem) and tasimelteon (Hetlioz) selectively bind to melatonin receptors (MT1 and MT2) and thus mimic the actions of melatonin, a hormone that regulates sleep-wake cycles. Tasimelteon is primarily used for non-24-hour sleep-wake disorder, common in blind patients. They are also used to treat conditions like insomnia...
Neurochemical Transmission: Sites of Drug Action

