The central projections of somatic, visceral and muscle unmyelinated C-fibers were examined in the guinea pig. The sensory modality of somatic C-afferent fibers were identified by natural stimuli, pinch, noxious heat and cooling. The central projections of high threshold mechanoreceptor (HTM), mechanical-cold nociceptor (MCN), polymodal nociceptor (PN) and low threshold mechanoreceptor (LTM) were observed in the cervical and lumbar cord. All somatic unmyelinated C-fibers projected into the superficial dorsal horn (laminae I, II) with a densely concentrated termination. The terminal patterns and course of fiber trajectories differed in the two levels of the spinal cord, cervical or lumbar. The visceral C-afferent fibers mainly projected to the lamina I,V, X, and contralateral V, X in the thoracic cord. Muscle C-afferent fibers from the lateral gastrocunemius were labeled in the lumbar cord. Terminal branches were located in laminae I, II and III in the several lumbar segments. The number and size of terminal swellings were compared among these C-afferent fibers to consider the natureof sensory processing.

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   To evaluate preemptive analgesic effects of etodolac which is a COX-2 selective inhibitor, and dexamethasone on postoperative pain, 34 patients aged 20 to 50 years undergoing tonsillectomy were enrolled in the study. In group E, etodolac 200 mg was orally administered 90 min before surgery. In group D, dexamethasone 8 mg wasadministered intravenously just after the induction of anesthesia. In group E+D, etodolac 200 mg was orallyadministered 90 min before surgery and dexamethasone 8 mg was administered intravenously after induction of anesthesia. In group C, any medication was not administered before surgery. Time until the patient complained maximum pain, NRS (numerical rating score) at 24 and 48 hours after the end of surgery and the total dose of analgesic suppository by 48 hours in each patient were recorded.
   Patients complained maximum pain within 1.5 hours after the end of surgery in all groups and the onset of pain did not differ among groups. NRS as the patients complained maximum pain was not statistically significantly different among groups. NRS at 24 hours after the end of surgery showed statistically significant improvement in group E+D compared to group E, D and C. NRS at 48 hours after the end of surgery showed statistically significant improvement in group E+D compared to group E, D and C. Moreover NRS at 48 hours after the end of surgery there were statistically significant differences between group E and C. Total dose of analgesic suppository by 48 hours was less in the group E and E+D than in the group C and D.
   Dexamethasone alone had no effect on postoperative pain at points of evaluation. Whereas, etodolac was analgesic 24 and 48 hours after the surgery, although the effect was scarce immediately after the surgery. An additive effect between both drugs was observed. These results suggest that preoperative etodolac with or without dexamethasone seems efficacious for the control of postoperative pain in tonsillectomy patients.

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