Functional characterization of histamine receptor subtypes in a human bronchial epithelial cell line.

Histamine is a well-known mediator eliciting a broad range of responses in different cell types. Four different subtypes of G protein-coupled histamine receptors (H1-H4) have been cloned and pharmacologically characterized. However, involvement of the different histamine receptor subtypes in immunomodulatory functions of bronchial epithelium has only been investigated marginally.

The serotoninergic receptors of human dendritic cells: identification and coupling to cytokine release.

The neurotransmitter 5-hydroxytryptamine (5-HT), commonly known as serotonin, is stored at peripheral sites in mast cells and released from this peripheral source upon IgE cross-linking. In this study, we investigated the expression of serotoninergic receptors (5-HTR), the signaling pathway, and biological activity of 5-HT on human dendritic cells (DC), showing that immature and mature DC expressed mRNA for different serotoninergic receptors. Thereby, the mRNA of 5-HTR(1B), 5-HTR(1E), 5-HTR(2A), 5-HTR(2B), one splicing variant of the 5-HTR(3), 5-HTR(4), and 5-HTR(7) receptors were detected.