In a final instance, all the very important functions conducted by the human brain depend on the transmission of signals across nerve cells. This synaptic transmission of signals is mediated by a great variety of proteins embedded in the membrane of the neurons. In spite of their tremendous importance for brain function, relatively little is known about how neurotransmitter receptors and ion channels of the human brain work.

To gain some insights on the functioning of receptors and channels many approaches have been used. A brief account will be made of the use of Xenopus oocytes to study receptors and channels of normal and diseased brains.