[5] The H3 receptor has also been shown to presynaptically inhibit the release of a number of other neurotransmitters (i.e. it acts as an inhibitory heteroreceptor) including, but probably not limited to dopamine, GABA, acetylcholine, noradrenaline, histamine and serotonin.

There is much interest in the histamine H3 receptor as a potential therapeutic target because of its involvement in the neuronal mechanism behind many cognitive disorders and especially its location in the central nervous system.

[8] The diverse expression of H3 receptors throughout the cortex and subcortex indicates its ability to modulate the release of a large number of neurotransmitters.

[11] These subtypes all have subtle difference in their pharmacology (and presumably distribution, based on studies in rats) but the exact physiological role of these isoforms is still unclear.

Some examples are: These include:[13] The H3-receptor is a promising potential therapeutical target for many (cognitive) disorders that are caused by a histaminergic H3R dysfunction, because it is linked to the central nervous system and its regulation of other neurotransmitters.