Spiroxatrine is a drug which acts as a selective antagonist at both the 5-HT1A receptor and the α2 adrenergic receptor. Spiroxatrine was identified as a moderately potent but non-selective agonist at the human nociceptin/orphanin FQ receptor, ORL1

Monatepil is a calcium antagonist that, as do existing calcium antagonists, inhibits the influx of extracellular Ca 2 + through voltage-dependent Ca 2 + channels. It is a new type of antihypertensive agent. Its unique chemical structure was specially designed with intrinsic calcium antagonist and a1 -adrenoceptor-blocking moieties, creating a dual mechanism of action. Positive effects on plasma lipid metabolism are derived from the a1 -adrenoceptor-blocking activity and the antiatherosclerotic effect derives from the calcium antagonist properties. The novel structure of monatepil produces a slow onset of action and a long-lasting antihypertensive effect in experimental animals.

Cinuperone is an antagonist of D2, alpha1 adrenergic and sigma receptors. The drug selectively inhibits dopamine agonists-dependent behaviors, mediated by the limbic system. The clinical development of the drug as an antipsychotic was terminated due to orthostasis.

Aplindore (DAB-452) is a small molecule that displays potent dopamine D2 receptor partial agonist activity in in vitro and in vivo assays and is predicted to have antipsychotic efficacy without motor side effects. Aplindore had been in phase II clinical trials for the treatment of Parkinson's disease and restless legs syndrome. Aplindore was generally well tolerated and there were no withdrawals due to adverse events and no serious adverse events.

Pelanserin is an antagonist of the serotonin 5-HT2 receptor and blocks alpha 1-adrenoceptor. Experiments on dogs have revealed that pelanserin showed adequate pharmacokinetic and pharmacodynamics profiles as an antihypertensive agent that is why the drug possessed potential therapeutic usefulness in the treatment of hypertension. Pelanserin was undergoing phase II clinical trials by Cinvestav in Mexico; however, these studied were discontinued.

Eptapirone is a potent, selective and efficacious 5-HT1A receptor agonist. In rats, it is readily bioavailable after oral administration. Likely, because of its high efficacy at 5-HT1A receptors, Eptapirone exerted powerful antidepressant- and anxiolytic-like activity in animal models. Eptapirone given in the evening suppresses REM (rapid eye movement) sleep more than buspirone and implies a greater central effect on serotonin receptors, which is consistent with the preclinical data that indicate it has greater efficacy than buspirone. It has little effect on other sleep stages. Eptapirone has been in phase I clinical trials for the treatment of anxiety and major depressive disorder. However, this research has been discontinued.

Mafoprazine is a phenylpiperazine derivative exerting postsynaptic dopamine D2 receptor blocking activity and alpha-adrenergic activity (alpha 1 receptor blocking activity and alpha 2 receptor stimulating activity). In animal models, mafoprazine demonstrated antipsychotic, aggression-inhibiting and cataleptogenic actions.

McN-5652 is one of a series of substituted pyrrolo-isoquinolines that, as a group, potently inhibit the uptake of one or more of the monoamines, norepinephrine, serotonin and dopamine. Receptor binding experiments indicated that McN-5652 has a weak affinity for serotonin 5-HT2 and alpha-1 adrenergic receptors. Abnormalities of the 5-HT transporter have been suggested in mood disorders, since it is one of the major binding sites of antidepressants. (+)-[11C]McN 5652 is an appropriate radiotracer to quantify 5-HT transporters in regions with relatively high concentration of 5-HT transporters, such as the midbrain, thalamus, and basal ganglia, and should prove useful in elucidating abnormalities of 5-HT transmission in neuropsychiatric conditions.