Abstract
The chemosensory capacity of the somatosensory system relies on the appropriate expression of chemoreceptors, which detect chemical stimuli and transduce sensory information into cellular signals. Knowledge of the complete repertoire of the chemoreceptors expressed in human sensory ganglia is lacking. This study employed the next-generation sequencing technique (RNA-Seq) to conduct the first expression analysis of human trigeminal ganglia (TG) and dorsal root ganglia (DRG). We analyzed the data with a focus on G-protein coupled receptors (GPCRs) and ion channels, which are (potentially) involved in chemosensation by somatosensory neurons in the human TG and DRG. For years, transient receptor potential (TRP) channels have been considered the main group of receptors for chemosensation in the trigeminal system. Interestingly, we could show that sensory ganglia also express a panel of different olfactory receptors (ORs) with putative chemosensory function. To characterize OR expression in more detail, we performed microarray, semi-quantitative RT-PCR experiments, and immunohistochemical staining. Additionally, we analyzed the expression data to identify further known or putative classes of chemoreceptors in the human TG and DRG. Our results give an overview of the major classes of chemoreceptors expressed in the human TG and DRG and provide the basis for a broader understanding of the reception of chemical cues.
Highlights
Detection and processing of environmental chemosensory information is important for living
We analyzed the transcriptomes of human trigeminal ganglia (TG) and dorsal root ganglia (DRG) to assess the expression of chemoreceptor genes in these ganglia
As RNA from the complete ganglia was used for the RNA-Seq experiments, no distinction could be made between different cell types e.g., the neurons and satellite cells that represent the most abundant cell types in sensory ganglia [45]
Summary
Detection and processing of environmental chemosensory information is important for living. In addition to gustation and olfaction, the trigeminal system represents a third chemical sense and is provided by the Nervus trigeminus. The nasal cavity is innervated by the ophthalmic and maxillary branches of the trigeminal nerve. The trigeminal ganglia (TG) are located at the base of the scull and represent the cranial analogue of the spinal nerve-associated ganglia, the dorsal root ganglia (DRG). The cell bodies of the pseudounipolar TG and DRG neurons can terminate.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
