A fifth member of the monoamine transmitter group is histamine. That release histamine as their neurotransmitter is located in the hypothalamus and project to cerebral cortex, limbic system and thalamus.
Receptors
There are three types of histamine receptors. H1 receptors occur throughout the CNS with particularly high densities in the thalamus and hippocampus H2 receptors are concentrated in the striatum, hippocampus and thalamus and H3 receptors in cortex, hippocampus and amygdala.