DAMGO, a μ-Opioid Agonist and Cholecystokinin-Octapeptide Have Dual Modulatory Effects on Capsaicin-Activated Current in Rat Dorsal Root Ganglion Neurons

• 영문명: DAMGO, a μ-Opioid Agonist and Cholecystokinin-Octapeptide Have Dual Modulatory Effects on Capsaicin-Activated Current in Rat Dorsal Root Ganglion Neurons
• 발행기관: 대한생리학회-대한약리학회
• 저자명: Su-Yong Eun Jimok Kim Jihye Lee Sung Jun Jung Joo Min Park Yun Kyung Park Dongkwan Kim Sang Jeong Ki
• 간행물 정보: 『The Korean Journal of Physiology & Pharmacology』제5권 제1호, 71~78쪽, 전체 8쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 2001.01.01

영문 초록

Capsaicin, a pungent ingredient of hot pepper, elicits an intense burning pain when applied cutaneously and intradermally. Activation of capsaicin-gated channel in C-type dorsal root ganglion (DRG) neurons produces nonselective cationic currents. Although electrophysiological and biochemical properties of capsaicin-activated current (I_CAP) were studied, the regulatory mechanism and intracellular signaling pathway are still unclear. In the present study, we investigated the modulations of I_CAP by DAMGO (μ-opioid agonist) and cholecystokinin octapeptide (CCK-8). In 18 out of 86 cells, the amplitude of I_CAP was significantly increased by DAMGO and completely reversed after washout, while I_CAP was decreased by DAMGO in 25 cells. In 43 cells, DAMGO had no effect on I_CAP. Mean action potential duration was significantly different between increased-by-DAMGO group and decreased-by-DAMGO group. Mean amplitudes of I_H were not significantly different between both groups. CCK-8 reversibly enhanced the amplitude of I_CAP (5/13). DAMGO also increased I_CAP amplitude significantly in the same cells. The amplitude of I_CAP was increased in additive manner by combined applications of DAMGO and CCK-8 in these cells. These results suggest that DAMGO and CCK-8 can either increase or decrease I_CAP presumably depending on the subtypes of DRG cells and classified by electrophysiological properties.

키워드

Capsaicin Opioids Cholecystokinin Dorsal root ganglion Pain ANOVA analysis of variance DTT dithiothreitol Grp glucose-regulated protein HSP heat shock family of stress proteins Hsp heat shock protein PDBu phorbol 12,13-dibutyrate PKC