Mephedrone (4-methylmethcathinone) is a β-ketoamphetamine belonging to the family of synthetic cathinones, an emerging class of designer drugs known for their hallucinogenic and psychostimulant properties as well as for their abuse potential. Mephedrone is a stimulant of dopamine (DA) release and blocks its reuptake through its interaction with the dopamine transporter. Furthermore, it has some affinity for various 5-hydroxytryptamine (5-HT) receptor subtypes. Neurotoxic effect of mephedrone on 5-HT and DA systems remains controversial. Although some studies in animal models reported no damage to DA nerve endings in the striatum and no significant changes in brain monoamine levels, some others suggested a rapid reduction in 5-HT and DA transporter function. Persistent serotonergic deficits were observed after binge like treatment in a warm environment and in both serotonergic and dopaminergic nerve endings at high ambient temperature. Oxidative stress cytotoxicity and an increase in frontal cortex lipid peroxidation were also reported. Despite the re-classification of mephedrone as a Class B restricted substance by the United Kingdom and restrictive legislation by the United States, international policy regarding mephedrone control is still developing and interest in synthetic amphetamine-like drugs could drive the development of future mephedrone analogues.

Oxidopamine (6-Hydroxydopamine) is an antagonist of the neurotransmitter dopamine with potential antineoplastic activity. 6-Hydroxydopamine (6-HOD) can be taken up by selective adrenergic terminals, thereby causing acute degeneration of adrenergic terminals that leads to depletion of norepinephrine, and of dopamine in the dopamine-sensitive sites. This agent is auto-oxidated at physiological pH that leads to the formation of reactive free radicals, thereby leading to cytotoxicity in neural cells. 6-Hydroxydopamine is often used to induce CNS and sympathetic neural lesions that model aging and various nervous disorders in animal systems. The growth of C-1300 neuroblastoma was markedly slowed in 6-hydroxydopamine-treated mice. The growth of the A-10 breast adenocarcinoma was also significantly retarded in 6-hydroxydopamine-treated mice but the growth of B-16 melanoma was not affected.

Tyramine is a naturally occurring monoamine compound and trace amine derived from the amino acid tyrosine. Tyramine occurs widely in plants and animals, and is metabolized by the enzyme monoamine oxidase. Tyramine is an alpha-adrenergic agonist. Hypertension can occur, from ingestion of tyramine-rich foods in conjunction with monoamine oxidase inhibitors. The possibility that tyramine acts directly as a neurotransmitter was revealed by the discovery of a G protein-coupled receptor with high affinity for tyramine, called TAAR. It exhibits sympathomimetic effects by causing the release of endogenic norepinephrine. It has been used in mydriatic eyedrops. This has been said to reduce the intraocular pressure in rabbits and in some patients with open-angle glaucoma.