H₃ Receptor Agonist

N-Methylhistamine dihydrochloride (Nα-Methylhistamine dihydrochloride) is a non-selective Histamine receptor agonist. N-Methylhistamine dihydrochloride activates histamine H₁, H₂ and H₃ receptors; it stimulates central H₁ receptors by activating sympathetic α and β adrenergic receptors to inhibit intestinal transit, exerts dose-dependent inhibition on intestinal transit, reduces histamine turnover in mouse brains, and increases gastric acid secretion without altering plasma gastrin concentrations. N-Methylhistamine dihydrochloride produces a pH-dependent, voltage-independent potentiating effect on acid-sensing ion channel 1a, and shows no significant activity toward homologous ASIC2a channels. N-Methylhistamine dihydrochloride can be used in studies related to Helicobacter pylori infection.

MK-3134 is an orally active, brain-penetrant and selective histamine H3 receptor inverse agonist. MK-3134 modulates histaminergic neurotransmission, decreases constitutive H3 receptor signaling, releases tonic inhibition of neurotransmitter release, potentiates neurotransmission, and may enhance cholinergic neurotransmission. MK-3134 can be used for the research of Alzheimer's disease.

(R)-(-)-α-Methylhistamine dihydrochloride is a potent, selective and brain-penetrant agonist of H3 histamine receptor, with a K_d of 50.3 nM. (R)-(-)-α-Methylhistamine dihydrochloride can enhance memory retention, attenuates memory impairment in rats.

Imetit dihydrobromide (VUF 8325 dihydrobromide) is a high affinity and potent agonist of histamine H3 and H4 receptors, with K_i values of 0.3 and 2.7 nM, respectively. Imetit mimics histamine effect in triggering a shape change in eosinophils (EC₅₀=25 nM).

(R)-(-)-α-Methylhistamine dihydrobromide is a potent, selective and brain-penetrant agonist of H3 histamine receptor, with a K_d of 50.3 nM. (R)-(-)-α-Methylhistamine dihydrobromide can enhance memory retention, attenuates memory impairment in rats.

VUF5207, an Impentamine (HY-107564) analogue, is a partial agonist of histamine H3 receptor.

H3R antagonist 5 (Compound 1b) is a selective histamine H3 receptor inverse agonist with a IC₅₀ of 0.54 nM and the ability to cross the blood-brain barrier. H3R antagonist 5 can be used in central nervous system-related research.

GR 175737 is a partial histamine H3 receptor agonist, with an EC₅₀ of 7.8 nM. GR 175737 can be used in the research of inflammatory diseases.