Sun Huahua, Liu Yang, Li Jian, Cang Xinzhu, Bao Haibo, Liu Zewen
Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China.
Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China; Changzhou Entry-Exit Inspection and Quarantine Bureau, Longjin Road 1268, Changzhou 213022, China.
Insect Biochem Mol Biol. 2017 Feb;81:32-40. doi: 10.1016/j.ibmb.2016.11.009. Epub 2016 Dec 20.
The american cockroach (Periplaneta americana) dorsal unpaired median (DUM) neurons provide an native tool to analyze the functional and pharmacological properties of ion channels and membrane receptors, such as nicotine acetylcholine receptors (nAChRs). Here the imidacloprid-activated nAChR subtypes were examined in DUM neurons by the patch-clamp technique and the potential subunits involved in important subtypes were analyzed by combining with RNA interference (RNAi) technique. Imidacloprid exerted agonist activities on one subtype in α-Bgt-sensitive nAChRs and another subtype in α-Bgt-resistant nAChRs, in which the α-Bgt-resistant subtype showed much higher sensitivity to imidacloprid than the α-Bgt-sensitive subtype, with the difference close to 200-fold. In α-Bgt-resistant nAChRs, nicotine exerted the agonist activity on two subtypes (nAChR1 and nAChR2), although imidacloprid only activated nAChR1. RNAi against Paα3, Paα8 and Paβ1 significantly reduced both imidacloprid- and nicotine-activated currents on nAChR1. In contrast, RNAi against Paα1, Paα2 and Paβ1 decreased nicotine-activated currents on nAChR2. The results indicated that, in α-Bgt-resistant nAChRs, Paα3, Paα8 and Paβ1 might be involved in the subunit composition of nAChR1, and Paα1, Paα2 and Paβ1 in nAChR2. In summary, from the present study and previous reports, we deduced that there are at least three nAChR subtypes that are sensitive to imidacloprid in the cockroach DUM neurons.
美洲大蠊（Periplaneta americana）的背侧不成对中间神经元（DUM）为分析离子通道和膜受体（如尼古丁乙酰胆碱受体，nAChRs）的功能和药理学特性提供了一个天然工具。在此，通过膜片钳技术研究了吡虫啉激活的nAChR亚型，并结合RNA干扰（RNAi）技术分析了重要亚型中可能涉及的亚基。吡虫啉对α-银环蛇毒素（α-Bgt）敏感的nAChRs中的一种亚型和α-Bgt抗性的nAChRs中的另一种亚型具有激动剂活性，其中α-Bgt抗性亚型对吡虫啉的敏感性比α-Bgt敏感亚型高得多，差异接近200倍。在α-Bgt抗性的nAChRs中，尼古丁对两种亚型（nAChR1和nAChR2）具有激动剂活性，尽管吡虫啉仅激活nAChR1。针对Paα3、Paα8和Paβ1的RNAi显著降低了nAChR1上吡虫啉和尼古丁激活的电流。相反，针对Paα1、Paα2和Paβ1的RNAi降低了nAChR2上尼古丁激活的电流。结果表明，在α-Bgt抗性的nAChRs中，Paα3、Paα8和Paβ1可能参与nAChR1的亚基组成，而Paα1、Paα2和Paβ1参与nAChR2的亚基组成。总之，从本研究和先前的报道中，我们推断在蟑螂DUM神经元中至少有三种对吡虫啉敏感的nAChR亚型。
