Download Supplemental Figure 1. Unequivocal distinction of mossy fiber

Supplemental Figure 1. Unequivocal
distinction of mossy fiber boutons from
dendrites of CA3 pyramidal neurons at
34 °C. A, Whole-cell voltage-clamp
recordings from a mossy fiber bouton
(MFB, left; holding potential -80 mV)
and an apical CA3 pyramidal neuron
dendrite (CA3-P dendrite, right; ~ 40
µm from the soma; holding potential
-70 mV) in the hippocampal CA3
stratum
lucidum.
B,
Capacitive
transients in response to a subthreshold 10 mV depolarizing voltage
command (100 ms). Input resistances
were 1.3 GΩ (MFB) and 110 MΩ
(dendrite). Series resistances typically
range from 30 to 100 MΩ. C, Sodium
currents in response to a suprathreshold voltage command to -40 mV.
Note the instant onset and fast kinetics
of the axonal sodium current compared
to that of the dendrite. D, Action
potentials evoked by local brief current
injection and recorded in the current
clamp configuration. AP-half-durations
were 360 µs (MFB) and 920 µs
(dendrite).
In all recordings, patched structures
were identified using procedures A
through C, and depending on the
intracellular solution, D. In Cs-based
solutions, identification and verification
by means of procedures B and C are
possible (in addition to A) if performed
immediately after break-in. (Recordings
were made with the same potassiumchloride-based internal solution using
pipettes with an open tip resistance of
10 MΩ.)