Figure 4.

The glossopharyngeal nerve does not functionally regenerate within 35 d following nerve section. A, Foliate taste buds from sham rats stained with cytokeratin-20 have a characteristic elongated shape and are oriented with taste pores (white arrows) adjacent to the epithelium. B, In contrast, foliate taste buds from rats that underwent glossopharyngeal nerve section 35 d before tissue collection had taste buds with rounded shape, did not exhibit visible taste pores (white arrowheads) and were located further away from the epithelium compared with shams. C, Whole nerve recordings from the glossopharyngeal nerve of a sham rat showed robust, sustained taste responses to a variety of stimuli. D, Whole nerve recordings from the glossopharyngeal nerve of a rat that underwent glossopharyngeal nerve section 35 d before recording showed no taste responses to a variety of taste stimuli. The transient responses to each stimulus in C and D likely reflect temperature and tactile responses. Scale bar: A, 50 μm. Calibration: C, 15 s.