Different Peas in the Same Pod: The Histaminergic Neuronal Heterogeneity

Whole-brain mapping of histaminergic projections in mouse brain

“…Early study used retrograde virus to explore the histaminergic distribution and found that histaminergic neurons in different subregions of TMN can project to all major downstream regions ( 23 , 24 ). However, later studies gave different views ( 25 ); some researchers found that different external stimulations can activate different subsets and numbers of histaminergic neurons in TMN ( 26 , 27 ), which indicated functional heterogeneity of histaminergic neuron subpopulations. What’s more, it has been proved by the microdialysis experiment that the increased levels of histamine in the downstream brain regions are different when histaminergic neurons are activated by different pharmacological reagents ( 28 – 30 ), suggesting the receptor heterogeneity of histaminergic neurons.…”