교감신경 중재 통증 보유 모델 쥐에서 교감신경 활동에 의한 배근절세포의 흥분성

• Published in: The Korean journal of pain Vol. 9; no. 1; pp. 26 - 38
• Main Authors: 임중우, Joong Woo Leem, 강민정, Min Jung Kang, 백광
• Format: Journal Article
• Language: Korean
• Published: 대한통증학회 1996
• Subjects: Sympathetically mediated pain; Dorsal root ganglion; Alpha-2 adrenoreceptor; Neuropathic pain
• ISSN: 2005-9159; 1226-2579; 2093-0569

In a normal state, sympathetic efferent activity does not elicit discharges of sensory neurons, whereas it becomes associated with and excites sensory neurons in a patho- physiological state such as injury to a peripheral nerve. Although this sympathetic-sensory interaction is reportedly adrenergic, involved subtypes of adrenoreceptors are not yet clearly revealed. The purpose of this study was to determine which adrenoreceptor sub- types were involved in sympathetic-sensory interaction that was developed in rats with an experimental peripheral neuropathy. Using rats that received a tight ligation of one or two of L4-L6 spinal nerves 10-15 days previously, a recording was made from afferent fibers in microfilaments teased from the dorsal root that was in continuity with the ligated spinal nerve. Electrical stimulation of sympathetic preganglionic fibers in T13 or Ll ventral root (50 Hz, 2-5 mA, 0.5 ms pulse duration, l0sec) was made to see if the activity of recorded afferents was modulated. About half of afferents showing spontaneous discharges responded to sympathetic stimu- lation, and had the conduction velocities in the A-fiber range. Most of the sympathetically induced afferent responses were excitation. This sympathetically induced exciitation oc- curred in the dorsal root ganglion (DRG), and was blocked by yohimbine (a.. blocker), nei- ther by propranolol 0 blocker) nor by prazosine (ai blocker). The results suggest that after spinal nerve ligation, sympathetic efferents interact with sensory neurons having A-fiber axons in DRG where adrenaline released from sympathetic nerve endings excites the activity of sensory neurons by acting on 2-adrenoreceptors. This 2-adrenoreceptor mediated excitation of sensory neurons may account for sympathetic in- volvement in neuropathic pain.