试用胆碱能受体学说，说明有机磷中毒发生的症状及主要治疗药物原理。
参考答案：
有机磷中毒是因为它抑制胆碱酯酶的活性，使神经末梢释放的递质Ach不能及时降解失活，造成Ach堆积过多而出现胆碱能神经活动过度增强的症状。如Ach与瞳孔括约肌、支气管平滑肌、胃肠道平滑肌、逼尿肌、涎腺、汗腺及心肌等细胞膜上的M受体结合，导致瞳孔缩小、支气管痉挛、肠胃运动增强、腹痛、腹泻、大小便失禁、流涎、大汗淋漓、心跳减慢甚至停搏等症状。Ach还可与骨骼肌细胞膜上的N受体结合，引起全身肌肉颤动。临床上可使用大剂量阿托品阻断M受体，同时使用氯磷定等药物恢复胆碱酯酶的活性，以达到救治的目的
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| I can still remember when I met my best friend. She had just moved into the neighborhood and her grandmother brought her down to 1 me. I hid behind my mother and she hid behind her grandmother, 2 to look at each other. Soon we lost the 3 and started playing with each other. In the 7th grade, I first lost touch with her. She was 4 family problems and I deserted her to be with the 5 people. None of my new friends liked her as much as I did because they knew she had 6 . However, every summer we 7 always sit at each other's house, watch soap operas, and talk about all the boys we liked. It was last year when I noticed the problem. I guess I was 8 devoted in high school to 9 she needed someone there. Anyway, she made a new best friend and so did I. Then I didn't know why, 10 she started cutting herself! She then was diagnosed(诊断)with clinical depression. At first, I was very 11 , but we still stayed in 12 I wanted to be there with her since her new best friend basically 13 her and people were calling her 14 . Yesterday she came to me and said, "I never knew what a best friend was 15 you, the only person, would stop me cutting. I 16 your help so much, and you didn't even know you were 17 me." We both cried. And I guess a kind of 18 from my life so far is never to give up on your friends. Even if they aren't as cool as others, or people think they are crazy, they need 19 there. If you desert them, you will only be 20 yourself. | ||||
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