Histamine is a neurotransmitter responsible for central regulation of inflammatory reactions. Initial studies were done by Sir Henry Dale in 1993. Histamine acts on its four type of receptors. H1 and H2 are well-established with pharmacological status. H1 receptors are mainly linked with inflammatory responses and developed to mitigate the inflammatory symptoms. While H2 antagonists are established with their role in decreasing basal gastric secretions by decreasing the cyclic adenylyl mono phosphate (cAMP), thus used as therapy line for gastric ulcers. H3 being located centrally imparts its central effects in cognitive functions that are pain, sleep, and memory modulation of neurotransmitters release including, dopamine, acetylcholine, noradrenalin and serotonin. H4 is discovered recently during cloning of H3 and found on immune related cells as, mast cells, T cells and dendrites. Experimental studies are helping in development of more pharmacologically worth drugs that can increase the quality of life.
Histamine receptors as drug target: Current and future therapeutics.
