The effects of application of dentin desensitizer containing glutaraldehyde (Gluma Desensitizer) and dentin adhesive system (All Bond 2) to the exposed dentin on the intradental nerve activity (INA) and the occluding aspects of dentinal tubules were investigated in cat canine teeth. Single pulp nerve units were dissected from the inferior alveolar nerve and indentified as $A{delta}$-fiber units. The INAs elicited by 4M NaCl before and after the application of each experimental agent were compared. The morphological changes of exposed dentin surfaces and dentinal tubules in the dentin specimens used to record INAs were observed by SEM. The results obtained were as follows. 1. Eight $A{delta}$-fiber units (conduction velocity: $8.0{pm}4.0m$/sec) were identified. 4M NaCl evoked an irregular burst of action potentials which ceased immediately after washing. 2. In 4 $A{delta}$-fiber units, the change of INA after the application of Gluma Desensitizer was $133.9{pm}80.7%$ when it was compared with the INA before the application of the same agent. 3. In 4 $A{delta}$-fiber units, application of All Bond 2 completely abolished the INA induced by 4M NaCl. 4. In specimens applied with Gluma Desensitizer, the formation of hybrid layer as well as the identification of resin penetration and reaction products with proteins in dentinal tubules were not clearly observed in interface between dentin and adhesive resin. In specimens applied with All Bond 2, the gap width of 2-$3{mu}m$ was formed between exposed dentin and adhesive resin, and the hybrid layer and resin tags were not clearly formed either.