PAIN RESEARCH
Online ISSN : 2187-4697
Print ISSN : 0915-8588
ISSN-L : 0915-8588
原著
カエル坐骨神経の複合活動電位に及ぼすアロマ精油成分の抑制作用
大坪 瀬奈藤田 亜美松下 晋大蒋 昌宇熊本 栄一
著者情報
ジャーナル フリー

2014 年 29 巻 1 号 p. 17-30

詳細
抄録

   Although the application of aroma–oil compounds contained in plants such as lavender to the skin produces a local anesthetic effect, cellular mechanisms for this effect have not been fully examined yet. Since some of aroma oil–derived chemicals modulate transient receptor potential (TRP) channels expressed in primary–afferent neurons, this modulation may be involved in the local anesthetic effect. We have previously reported that plant–derived chemicals (capsaicin, menthol and allyl isothiocyanate, which activate TRPV1, TRPM8 and TRPA1 channels, respectively) at high concentrations inhibit fast–conducting and Na+–channel blocker tetrodotoxin–sensitive compound action potentials (CAPs) recorded from the frog sciatic nerve without TRP activation. The CAPs were also inhibited by opioids and adrenoceptor agonists without the activation of receptors for the agonists. The inhibitory actions were specific to their chemical structures. The present study examined how various aroma–oil compounds affect frog sciatic nerve CAPs by using the air–gap method. Lavender–oil compounds, linalyl acetate and linalool, reduced CAP peak amplitudes with the half–maximal inhibitory concentration (IC50) values of 0.49 mM and 1.65 mM, respectively. When compared with local anesthetics’ actions reported previously in the frog sciatic nerve, the linalyl acetate activity was similar to those of lidocaine, ropivacaine and cocaine (0.74, 0.34 and 0.80 mM, respectively), while the linalool one was comparable to that (2.2 mM) of procaine. Citral, which activated TRPV1, TRPM8, TRPA1 and TRPV3 channels, attenuated CAP peak amplitudes with the IC50 value of 0.48 mM; this action was resistant to a non–selective TRP antagonist ruthenium red (0.3 mM). Camphor, a TRPV1 and TRPV3 agonist, also reduced CAP peak amplitudes (by 30% at 5 mM) in a manner insensitive to ruthenium red. With respect to other aroma–oil compounds, citronellal and rose oxide reduced CAP peak amplitudes with the IC50 values of 0.50 mM and 2.0 mM, respectively, while myrcene at a high concentration such as 5 mM hardly reduced CAP peak amplitudes. Taking into consideration previously–reported frog sciatic nerve data, an efficacy sequence of aroma–oil compounds for the CAP inhibi­tions was phenols (carbacrol: 0.35 mM; thymol: 0.42 mM; eugenol: 0.81 mM) ≧ aldehydes (citral and citronellal) ≧ esters (linaryl acetate) > alcohols (linalool; menthol: 0.93 – 1.1 mM) > ketones (pulegone: 1.4 mM; carbone: 1.4 – 1.6 mM; menthone: 1.5 – 2.3 mM) > oxides (rose oxide; cineole: 6.6 – 7.5 mM) ≫ hydrocarbons (myrcene; limonene: 8% inhibition at 10 mM), except for a ketone camphor that was less effective than oxides. It is suggested that aroma–oil compounds inhibit nerve conduction in a manner specific to their chemical structures; some of the compounds have efficacies comparable to those of local anesthetics. This result would serve to know aroma–oil compounds which may be useful as local anesthetics.

著者関連情報
© 2014 日本疼痛学会
前の記事 次の記事
feedback
Top