Transient receptor potential channel A1 and noxious cold responses in rat cutaneous nociceptors

The role of transient receptor potential channel A1 (TRPA1) in noxious cold sensation remains unclear. Some data support the hypothesis that TRPA1 is a transducer of noxious cold whilst other data contest it. In this study we investigated the role of TRPA1 in cold detection in cutaneous nociceptors in vivo using complementary experimental approaches. We used noxious withdrawal reflex electromyography, and single fibre recordings in vivo, to test the hypothesis that TRPA1-expressing primary afferents mediate noxious cold responses in anaesthetised rats. TRPV1 and TRPM8 agonists sensitise their cognate receptors to heat and cold stimuli respectively. Herein we show that the TRPA1 agonist cinnamaldehyde applied to the skin in anaesthetised rats did not sensitise noxious cold evoked hind limb withdrawal. In contrast, cinnamaldehyde did sensitise the C fibre-mediated noxious heat withdrawal, indicated by a significant drop in the withdrawal temperature. TRPA1 agonist thus sensitised the noxious reflex withdrawal to heat, but not cold. Thermal stimuli also sensitise transient receptor potential (TRP) channels to agonist. Activity evoked by capsaicin in teased primary afferent fibres showed a significant positive correlation with receptive field temperature, in both normal and Freund's complete adjuvant-induced cutaneous inflammation. Altering the temperature of the receptive field did not modulate TRPA1 agonist evoked-activity in cutaneous primary afferents, in either normal or inflamed skin. In addition, block of the TRPA1 channel with Ruthenium Red did not inhibit cold evoked activity in either cinnamaldehyde sensitive or insensitive cold responsive nociceptors. In cinnamaldehyde-sensitive–cold-sensitive afferents, although TRPA1 agonist-evoked activity was totally abolished by Ruthenium Red, cold evoked activity was unaffected by channel blockade. We conclude that these results do not support the hypothesis that TRPA1-expressing cutaneous afferents play an important role in noxious cold responses.     

A novel type of cold-sensitive neuron in rat dorsal root ganglia with rapid adaptation to cooling stimuli

Cold sensing in mammals is heterogeneous and more than one type of receptor molecule is likely to be involved in the transduction process. Most features of innocuous cold receptors have been explained by TRPM8, the cold and menthol receptor, but their fast adaptation to cooling has not yet been reproduced in cellular systems. In this study we have used a newly developed system for applying fast thermal stimuli to dissociated dorsal root ganglia (DRG) neurons from young rats (150-200 g) in primary culture. We describe a novel type of cold-sensitive rat DRG neuron with rapid adaptation to cooling. These cells (4.3% of the total DRG population) do not express either TRPM8 or the other cold-activated TRP channel, TRPA1, and the epithelial sodium channel (ENaC) is not involved in their transduction. Increases in intracellular calcium induced by cooling in rapidly adapting neurons are caused by calcium entry. These neurons express a large and rapidly adapting cold-induced inward current with a time constant of adaptation in the seconds range, and may correspond to the rapidly adapting cold receptors described in vivo.     

高效液相色谱法同时测定纯阳正气胶囊中3种成分的含量

目的 采用高效液相色谱法建立同时测定纯阳正气胶囊中橙皮苷、桂皮醛和丁香酚含量的方法。方法 色谱柱为Agilent PorosheⅡ120 EC-C₁₈(4.6 mm×150 mm,4μm),以乙腈-水为流动相梯度洗脱,柱温35℃,流速1.0 ml/min,检测波长284 nm。结果 方法学验证表明,橙皮苷、桂皮醛和丁香酚3种成分线性关系良好(r≥0.999 9),精密度小于2.0%,平均加样回收率在98.0%～101.9%之间,稳定性和重复性的RSD均<3.0%,符合方法学要求。结论 该方法简便、稳定、重复性好、准确可靠,可用于纯阳正气胶囊的质量控制。     

不同的炮制品及煎煮方法对肉桂水提液有效成分的影响

目的：研究肉桂有效成分随煎煮时间的变化规律,找出肉桂最佳的炮制、煎煮方法。方法：1,浸泡时间分浸泡0min(直接后下)与浸泡30min煎煮两种方式;2,炮制分块状、切丝、打粉;3,煎煮时间分别以5、10、15、20、30、40min的时间节点,以这3个因素采用正交试验,提取肉桂水提液,用HPLC法测定桂皮醛含量。结果：粉末状肉桂和丝状肉桂的桂皮醛提取率高于块状肉桂,直接后下的煎煮方法的桂皮醛提取率高于浸泡煎煮。结论：切丝的炮制品和直接后下5min的煎煮方法是最有效保存肉桂水提液有效成分的方法。     

Interaction of cinnamaldehyde (a sensitizer in fragrance) with protein

Formation of a cinnamaldehyde-protein conjugate in the skin by reaction of cinnamaldehyde with nucleophilic groups in proteins is considered to be responsible for the observed immunogenicity. The kinetics of the reaction of bovine serum albumin with cinnamaldehyde in aqueous solution at 30 degrees C have been investigated, and the rate of formation of conjugate over the pH range 6.4-10.5 showed a first-order dependence on cinnamaldehyde concentration. The cinnamaldehyde binding sites on the protein appeared mostly or exclusively to be the thiol groups of cysteine residues.     

Cheilitis granulomatosa—an unusual diet for an unusual disorder

A case of cheilitis granulomatosa, a rare inflammatory disorder of unknown origin is reported. The condition produces non-tender, persistent swelling of one or both lips and primarily affects young adults. The patient had a positive patch test to salicylate and cinnamaldehyde, and was therefore treated with an exclusion diet avoiding these substances. After 4.5 months on the exclusion diet, a 75% reduction in symptoms was reported.     

多指标综合评分法对肉桂不同软化方法的比较研究

目的以水溶性浸出物、挥发油、肉桂醛及肉桂酸的含量为指标对浸泡法、淋润法、减压冷浸法这3种软化方法进行研究,选出肉桂的最佳软化方法。方法按照《中国药典》规定的方法测定各组样品的水溶性浸出物及挥发油含量,采用高效液相色谱法(HPLC)测定肉桂醛及肉桂酸的含量,采用多指标综合评分法分析结果。结果各指标综合评分结果为减压冷浸法浸泡法原药材淋润法。结论减压冷浸法制得的饮片色泽好、香气浓烈,软化时间短,有效成分损失较少,减压冷浸法为肉桂最佳的软化工艺。     

HPLC法测定颈椎通络丸桂皮醛、芍药苷含量

目的:采用HPLC方法测定颈椎通络丸桂皮醛、芍药苷含量。方法:色谱柱C18(200×4.6mm,5μm);桂皮醛、芍药苷流动相与测定波长分别为甲醇-1%磷酸(300:200)与乙腈-0.1%磷酸溶液(22:78);290nm与230nm;流速:1mL.min-1;结果:桂皮醛与芍药苷分别在0.02～0.64?g与0.0182～0.546?g之间成线性关系(r=0.999)。回收率分别为100.0%与103.0%;颈椎通络丸桂皮醛、芍药苷平均含量分别为0.24 mg﹒g-1、0.16 mg﹒g–1。结论:采用本法测定颈椎通络丸桂皮醛、芍药苷含量,操作简便,准确可靠,可用于制定该药品的质量控制指标之一。     

中药材药物防霉的研究

作者对多菌灵(BCM)、丁香油、挂皮醛的防霉作用进行了研究。结果表明:桂皮醛、丁香油防霉作用明显,桂皮醛优于丁香油。BCM仅对曲霉、青霉、木霉显示明显抑菌作用。经扫描电镜、透射电镜观察,桂皮醛可破坏真菌细胞壁,使胞浆凝固,细胞器消失。