题干

刺激某神经元会引起后一个神经元兴奋.当给予某种药物后,再刺激同一个神经元,发现神经冲动的传递被阻断,经检测,突触间隙中神经递质的含量比给药物前明显减少.该药物的作用机理是(  )

A:增强突触后膜的通透性

B:抑制突触后膜受体的功能

C:增强突触前膜的通透性

D:抑制突触前膜递质的释放

上一题 下一题 0.0难度 选择题 更新时间:2015-07-28 01:44:46

答案(点此获取答案解析)

D

同类题2

根据短文理解,选择正确答案。

    “Croeso I Gymru!,” If you don't know what this means, read on to find out more.

    When you cross over the border from England into Wales, you don't have to show your passport but you do notice a difference immediately. All the road markings and signs are shown in two languages — English and Welsh (威尔士语). Not all visitors to Britain know that other languages are spoken here. There's the Gaelic (盖尔语) language in Scotland and a few people speak Cornish (康沃尔语)in the southwest of England, but the most widely spoken language in the UK besides English is Welsh.

    Perhaps the first Welsh word you'll see on the road into Wales is ARAF. There's a helpful English translation next to it — SLOW. As you can see, Welsh looks quite different from English. It sounds very different, too. Welsh looks and sounds so different from English because it's a Celtic language. Celtic cultures still exist around the edges of the UK — in Wales, Scotland and Northern Ireland and also in parts of France. For hundreds of years, almost everyone in Wales spoke Welsh, but nowadays there are about 600 thousand Welsh speakers — around 20% of the population.

    So is Welsh dying out? Not at all! Nowadays, all school children in Wales study Welsh and many choose to go to an all Welsh-speaking school. You can get public information in Welsh, speak Welsh in court or take a course at university in Welsh. People surf the Internet in Welsh, keep up with friends on Facebook and write blogs in Welsh.

    By the way, Croeso I Gymru!" means “Welcome to Wales!” 一 I hope you'll be able to visit it one day.