BIOL 3P34 Lecture Notes - Lecture 5: Patch Clamp, Pipette, Internal Control
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Single channel currents: channels alternate between open and closed states, (cid:862)(cid:373)i(cid:272)ros(cid:272)opi(cid:272) (cid:272)urre(cid:374)ts(cid:863) pa (10-12 a, can be used for ligand gated/ or voltage gated channels, duratio(cid:374) of (cid:272)ha(cid:374)(cid:374)els (cid:271)ei(cid:374)g ope(cid:374) is (cid:271)ased o(cid:374) the (cid:862)(cid:373)ea(cid:374) ope(cid:374) ti(cid:373)e(cid:863) Positive charge -> outside of cell = positive current. Positive charge -> into cell = negative current. Downwards deflections on patch clamp readings = -ve current. Upwards deflections on patch clamp readings = +ve current. Once a solution is a pipette is used, it cannot be changed. The solution that bathes the cell can be. Outside out patch: advantage: by changing bathing medium, anything that may activate a channel from the outside can be recorded, test neurotransmitter effect on activation, disadvantage: only able to record single, few ion channels. Can control ion concentration inside the recording pipette as well as in the bathing medium. Want ion cell concentrations to mimic natural ion concentrations.