Department of Physiology, Showa University School of Medicine, Tokyo 142-8555, Japan.
Department of Orthopedic Surgery, Showa University School of Medicine, Tokyo 142-8555, Japan.
Biomed Res. 2024;45(4):151-161. doi: 10.2220/biomedres.45.151.
Linalool and linalyl acetate are major components of lavender essential oil. These substances possess many biological activities, such as anti-inflammatory activity, analgesic and anxiolytic effects, and anticonvulsant properties, and they also induce modulation of neuronal activity in the autonomic nervous system. However, there are no reports of the direct effects of linalool on respiratory activity. In the present study, we analyzed the effects of linalool and linalyl acetate on central respiratory activity in the brainstem-spinal cord preparation isolated from newborn rats. Linalool dose-dependently decreased the rate of respiratory activity. This effect was reversed by bicuculline, suggesting that linalool enhanced inhibitory synaptic connections via GABAA receptors. In addition, linalool reduced the coefficient of variation of inspiratory burst intervals and thus could work to stabilize the respiratory rhythm. Linalyl acetate did not cause inhibitory effects as observed in linalool treatment. Linalool depressed burst activity of pre-inspiratory neurons in the medullary respiratory networks and increased the amplitude of inspiratory inhibitory postsynaptic potentials of pre-inspiratory neurons. We concluded that linalool caused inhibitory effects on respiratory rhythm generation mainly through activation of presynaptic GABAA receptors of pre-inspiratory neurons.
芳樟醇和乙酸芳樟酯是薰衣草精油的主要成分。这些物质具有许多生物活性，如抗炎活性、镇痛和抗焦虑作用以及抗惊厥特性，它们还可诱导自主神经系统中神经元活动的调节。然而，没有关于芳樟醇对呼吸活动的直接影响的报道。在本研究中，我们分析了芳樟醇和乙酸芳樟酯对从新生大鼠分离的脑干-脊髓脑片中央呼吸活动的影响。芳樟醇呈剂量依赖性降低呼吸活动的频率。这种作用被印防己毒素逆转，表明芳樟醇通过 GABA A 受体增强抑制性突触连接。此外，芳樟醇降低了吸气爆发间隔的变异系数，从而可以稳定呼吸节律。乙酸芳樟酯没有像在芳樟醇处理中观察到的那样引起抑制作用。芳樟醇抑制了延髓呼吸网络中吸气前神经元的爆发活动，并增加了吸气前神经元的抑制性突触后电位的幅度。我们得出结论，芳樟醇主要通过激活吸气前神经元的突触前 GABA A 受体对呼吸节律产生抑制作用。
