BIOL 4380 Lecture Notes - Lecture 3: Substantia Nigra, Halorhodopsin, Biological Neural Network

• School: York University
• Department: Biology
• Course: BIOL 4380
• Professor: Vladimir Belozerov

Document Summary

Now we want to do the opposite, manipulate the neuronal circuits and study the behaviour: Optogenetics: relies on certain transmembrane (ion) channels form bacteria, called bacteriorhodopsin, halorhodopsin and channelrhodopsin, very similar to rhodopsins found in our eyes. Bacterial opsins use the same chromophore as in retinal opsin to transduce light energy into chemical signal that activates channel proteins. Opsins modulate membrane currents when they absorb photons, light can be used to control nerve cell activity. Both bacteriorhodopsin and halorhodopsin are responsible for a hyperpolarizing effect. Bacteriorhodopsin is only permeable for protons and it takes them from inside and pumps them out. Halorhodopsin, is selective for cl- and takes it from out to in. Channelrhodopsin is capable of transporting different kinds of ions (both anions and cations). Which will provide for either depolarization or hyperpolarization. The wavelength of excitation and the specific type of channelrhodopsin will determine what ions are transported.