악안면 영역에서 동통을 평가하는 실험 모델의 개발과 항우울제가 동통에 미치는 영향 = DEVELOPMENT OF A PAIN ASSESSMENTMODEL ANDEFFETS OF ANTIDEPRESSANTS ON NOCICEPTIVEJAWOPENING REFLEX IN FREE MOVING RATS

다국어 초록 (Multilingual Abstract)

The purpose of the present study was development of a new pain assessment model that could be recorded in free moving rats to eliminate influences of anesthetic agents in orofacial area. Antinociceptive effects and mechanisms of tricyclic antidepressants is also investigated.
Fifty-five male Wistar rats (400-500gm) were anesthetized with an intraperitoneal injection of urethane (500㎎/㎏) and pentobarbital sodium (20㎎/㎏). Anesthetized rats were mounted in a sterotaxic instrument and a guide cannula was implanted in the lateral ventricle. The coordinates were 0.8㎜ posterior to bregma, 1.5㎜ lateral from midline and 0.4㎜ ventral from the skull. Stimulating electrodes implanted in the incisor pulp and recording electrodes were inserted into the anterior belly of digastric muscle. Stimulating and recording electrodes were led subcutaneously to miniature cranial connector sealed on the top of the skull with acrylic resin. Jaw opening reflex (JOR) was used as a pain assessment. Jaw opening reflex is elicited by noxious stimulation of the incisor and is quantified by the magnitude of electromyogram of digastric muscle (dEMG). After a 48 hours recovery period from surgery, JOR was recorded in free moving rats. Electrical shocks (200 sec duration. 0.5-2 ㎃ intensity, 0.5 ㎐) were delivered to the dental pulp. Twenty subsequent electromyograms were recorded from digastric muscle in free moving rats.
After intraperitoneal injection of 15㎎/㎏ imipramine or nortriptyline dEMG was suppressed to 64±6 or 56±8% of the control. Intraperitoneal injection of 30㎎/㎏ desipramine, imipramine or nortriptyline suppressed dEMG respectively to 44±9. 15±4, or 16±3% of the control. After intravenous injection of 12㎎/㎏ desipramine, imipramine or nortriptyline, dEMG was suppressed to 73±7, 50±4, or 66±7% of the control. Intravenous injection of 18㎎/㎏ desipramine, imipramine or nortriptyline suppressed dEMG respectively to 57±6, 12±3 or 6±2% of the control. To investigate the central mechanisms of antinociception of nortriptyline, naloxone, opioid receptor antagonist, methysergide, serotonergic receptor anatgonist and phentolamine, α-adrenergic receptor antagonist were injected into the lateral ventricle. Naloxone. methysergide, and phentolamine inhibited suppression of dEMG by intravenous injection of 18 ㎎/㎏ nortriptyline from 7±2 to 47±9, from 4±2 to 24±6. and from 4±1 to 51±7% of the control respectively.
These results suggest that antidepressant agents be able to modulate pain transmission in orofacial area. The analgesia produced by intraperitoneal and intraventous injection of antidepressants seems to be mediated by multiple pathways such as descending pain inhibitory system.

목차 (Table of Contents)

• Abstract
• I. 서론
• II. 대상 및 방법
• III. 성적
• IV. 고찰
• V. 요약
• 참고문헌