극저주파 자기장으로 유도한 생쥐의 통각과민에 α2-수용체의 관련성

Involvement of α2-Receptor in Extremely Low Frequency Magnetic Field-induced Hyperalgesia in Mice

The purpose of this study is to prove how magnetic field (MF) acts on sympathetic neuro-transmissions using thermal response. Mice were divided into two groups and each one was exposed to MF (20 G,24 hrs) or sham. Every vehicle or drugs were treated a half hour before the thermal response test. The pain threshold was lowered by MF (20 G,24 hrs) alone. This reduction of pain threshold by MF was not blocked by a single treatment of α1 -receptor antagonist (prazosin),α2- receptor agonist (clonidine, guanabenz),β1-receptor antagonist (atenolol) or β1, βSUB>2-receptor antagonist (propranolol). But administration of α2-receptor antagonist (yohimbine) completely inhibited the decrease in pain threshold by MF Moreover, it increased by high dose of yohimbine over normal condition. These results suggest that MF acts on sympathetic nerve terminal to induce hyperalgesia, in which pre-synaptic α2 receptor might be involved.