사춘기전 마우스 미측소핵의 아교질 신경세포에서 시트랄의 억제성 신경전달 조절에 대한 연구

다국어 초록 (Multilingual Abstract)

Citral (3,7-dimethyl-2,6-octadienal) is a monoterpene aldehyde consisting of isomers geranial and neral chemically. The substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc) is admitted as a key site of receiving and regulating orofacial nociceptive inputs. Although citral is known to be involved in antinociception, the action mechanism of citral on the SG neurons of the Vc has not been fully understood yet. In this study, I examined the direct membrane effects of citral and how citral mediates responses on the SG neurons of the Vc in juvenile mice using a whole-cell patch-clamp technique. Under high chloride pipette solution, citral showed repeatable inward currents that persisted in the presence of tetrodotoxin, a voltage-gated Na+ channel blocker, and 6-cyano-7-nitro-quinoxaline-2,3-dione, a non-N-methyl D-aspartate (NMDA) glutamate receptor antagonist, 2-amino-5-phosphonopentanoic acid, an NMDA receptor antagonist. However, the citral-induced inward currents were partially blocked by picrotoxin, a gamma-aminobutyric acid (GABA) type A receptor antagonist, or by strychnine, a glycine receptor antagonist. Further, the citral-induced responses were almost blocked by picrotoxin with strychnine. I also found that citral exhibited additive effect with GABA-induced inward currents and glycine-induced inward currents were potentiated by citral. In addition, citral suppressed the firing activities by positive current injection on the SG neurons of the Vc. Taken together, these results indicate that citral has glycine- and/or GABA-mimetic actions and suggest that citral might be a potential target for orofacial pain modulation by the activation of inhibitory neurotransmission in the SG area of the Vc.

keywords : Citral, GABAA receptor, Glycine receptor, Patch-clamp, Substantia gelatinosa neuron

목차 (Table of Contents)

• I. ABSTRACT ii
• II. INTRODUCTION 1
• III. MATERIALS & METHODS 3
• 1. Animals and brain slice preparation 3
• 2. Whole-cell patch-clamp recording 3
• 3. Chemicals 4
• 4. Statistics 5
• IV. RESULTS 6
• 1. Non-desensitizing and repeatable responses by citral 6
• 2. Direct postsynaptic action of citral on the SG neurons is not mediated by activation of ionotropic glutamate receptors 6
• 3. GABA -and glycine-mimetic actions of citral on the SG neurons 7
• 4. Effects of citral on the GABA, glycine and current-evoked responses 8
• V. DISCUSSION 10
• VI. FIGURES & LEGENDS 14
• VII. REFERENCES 23
• VIII. 국문초록 27