Specific carbohydrate expression by small-diameter subclasses of rabbit trigeminal, glossopharyngeal, and vagal afferent fibers studied with the lectin Ulex europaeus agglutinin I.

Lectin Ulex europaeus agglutinin I (UEAI), which binds to some alpha-L-fucose containing carbohydrates, specifically labeled a subset of trigeminal, glossopharyngeal, and vagal ganglion cells and their axons in the rabbit. The UEAI-positive trigeminal afferent fibers traveled through the spinal tract of the trigeminal nerve and terminated predominantly at the superficial laminae of the caudal region of the nucleus of the spinal trigeminal tract. The trajectory and termination regions of the UEAI-positive trigeminal afferent fibers as well as their small diameters suggest that they are C-fibers which mediate nociceptive and/or thermoceptive inputs. The UEAI-positive vagal and glossopharyngeal fibers were also of small diameter and traveled through the solitary tract. They projected to the nucleus of the solitary tract and the area postrema. No central neurons in the brainstem were labeled with UEAI. These results indicate that subsets of trigeminal, glossopharyngeal, and vagal primary sensory neurons express specific carbohydrates on their cell surfaces.