Maroxepin is a tetracyclic compound antagonizing activity of dopamine receptors. Maroxepin has a potent central nervous action and a strong sedative potential. Maroxepin exerts both antipsychotic and antidepressant properties.

Odapipam is a benzazepine with high affinity and selectivity for D1-dopamine receptors. Labeled with C-11, it has been used as a PET radiotracer to visualize D1 receptors both in striatal and extrastriatal areas, such as the prefrontal cortex. Odapipam inhibits dopamine D1 receptor binding in vitro with low nanomolar to picomolar dissociation constants. The affinity of [11C]NNC 756 for D1 receptors is 0.18 nM. Odapipam was tested in phase I of clinical trials for the treatment of psychotic disorders, but failed.

Carabersat is an anticonvulsant devoid of cardiovascular side effects with minimal central nervous system adverse actions. Carabersat does not bind to ion channels, purinergic, aminergic, opioid and other peptidergic receptors. It selectively interacts with its own binding site, which is not yet elucidated. Carabersat has no effect on sodium channels, GABAergic or glutamate pathways. Carabersat had been in phase II clinical trials for the treatment of epilepsy. It has a potential action in preventing migraines because it acts through an inhibition of the cortical spreading depression trigeminal nerve-induced vasodilatation in cats. Its good therapeutic index and the markedly reduced neurological impairments could make it a useful agent for migraine prophylaxis pending efficacy parameters of controlled studies, which are underway.

Emapunil acts as a selective agonist at the peripheral benzodiazepine receptor (TSPO). At the cellular level, the selective TSPO ligand XBD173 potentiated the amplitude and duration of GABA-mediated inhibitory postsynaptic currents in mouse medial prefrontal cortical neurons, which was prevented by finasteride. In animal and human trials, XBD173 produced rapid anxiolytic and anti-panic effects probably via newly synthesized neurosteroids, without producing sedation or withdrawal symptoms, and may represent a promising target for the development of fast-acting anxiolytics with a more favourable side-effect profile than benzodiazepines.

Etisulergine (CQ 32-084) is an ergoline derivative. Etisulergine stimulates both dopamine D1- and D2-receptors, antagonizes alpha-adrenergic and serotonin 5-HT2 receptors. Etisulergine demonstrated antiparkinsonian activity in patients.

Nomelidine (norzimelidine), the active N-demethylated metabolite of zimelidine, is a potent and specific inhibitor of [14C]5-HT uptake in synaptosome rich homogenates of rat hypothalamus. Nomelidine inhibits the uptake of 5-HT more potently than the parent compound. Zimelidine (ZIM) and its main active metabolite norzimelidine (NZIM) have been shown to preferentially inhibit 5-hydroxytryptamine (5-HT) neuronal uptake both in vitro and in vivo while having much less effect on noradrenaline (NA) uptake.

Valdipromide is an antidepressant.

Nicocodine is an opioid related to codeine. It is also an antitussive agent. Nicocodine exhibits at least twice the potency of codeine in clinical experiments. The study of the pharmacokinetic behaviour of nicocodine by means of blood and brain level curves of rats after i .v. application showed that the penetration of the blood brain barrier seems to be favoured for nicocodine. The detected peak concentration of nicocodine in brain after i.v. application is 4.4 times higher than the blood level values at the same time - codeine the main metabolite is detected in almost equal amounts in brain and blood. A comparative assay of codeine and nicocodine after p.o. application of equimolar doses per kg body weight revealed that predominantly codeine is found in brain and its peak value after nicocodine administration is 3-fold higher than after codeine administration. Nicocodine is hydrolysable to morphine and the WHO Expert Committee on Addiction-Producing Drugs (1962) recommended its international control as a narcotic, like other convertible drugs in the morphine series.

Etiocholanone is an androstane neurosteroid. Etiocholanone potentiates GABA-A receptor currents and exerts anticolvunsant properties in rodents. Etiocholanolone demostrates pyrogenic properties.

Mecloqualone is a quinazoline-class GABAergic and an analog of methaqualone. It acts as an agonist of the beta subtype of GABAa receptor and induces sedative, hypnotic and anxiolytic effects. Mecloqualone was marketed (mostly in france) under the names Nubrene and Casfen for the treatment of insomnia. Mecloqualone is no longer prescribed because of concerns about its potential for abuse and overdose. In the United States, it is registered as a Schedule-I non-narcotic controlled substance.