BIOL 3P34 Lecture 4: 4.
10 Oct 2016
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How long does a channel stay open. Channels alternate between open and closed states (cid:498)microscopic currents(cid:499) in pa (10-12) a (in this case currents are inwards) On the surface, high resistance seal between glass & membrane cell attached (record channel currents under pipette) Whole cell (dialyze cell: record whole cell currents) You can control the concentration of ions both inside the recording pipette as well as in the bath medium. *whether it mimics the intracellular or extracellular depends on the patch configuration used. Output polarity of a patch clamp-rig can differ. May be correct for whole-cell configuration inverted for cell-attached configuration this is the case for most commercial amplifiers but it may be reversed. Inward current across membrane is also inward current recorded by pipette. Inward membrane current is recorded as outward by pipette. Patch clamp recordings show: rectangular pulses of current (opening/closing, appear irregularly, near fixed amplitudes, variable durations, but mean open time (how would you calculate)
