BIOLOGY 3P03 Lecture 5: Voltage Clamp
5 Feb 2017
School
Department
Course
Professor
Document Summary
From h&h learnt that electrical activity in cells is far easier to analyze with a procedure known as voltage clamp. If behavior of ion channels depends on voltage & time, then the first step required to understand the underlying mechanisms to control 1 of the 2 variables (i. e. voltage easier to control than current) Under voltage clamp, the kinetic behavior of ion channels is at its simplest. From h&h also learnt that membrane permeability/conductance gm = f(vm, t) To study this process need to keep one variable constant (hence voltage) Advantages of squid giant axon for these experiments: can insert large wire electrodes, can perfuse axoplasm with solutions of known (cid:272)o(cid:374)(cid:272)e(cid:374)t(cid:396)atio(cid:374)s; a(cid:454)oplas(cid:373) (cid:272)a(cid:374) (cid:271)e (cid:858)(cid:396)olled out(cid:859) a(cid:374)d (cid:272)o(cid:374)te(cid:374)ts su(cid:271)stitute. Points to note on the 2 electrode voltage clamp. Two long wires inserted axially along squid giant axon one measure actual membrane potential; other passes current.
