Patch-clamp recording from mossy fiber terminals in hippocampal slices
1Institute of Physiology, University of Freiburg, Hermann-Herder-Strasse 7, D-79104 Freiburg, Germany. 2Independent Hertie Research Group, Max-Planck Institute for Brain Research, Deutschordenstrasse 46, D-60528 Frankfurt, Germany. Correspondence should be addressed to P.J. (email@example.com)
Rigorous analysis of synaptic transmission in the central nervous system requires access to presynaptic terminals. However, cortical terminals have been largely inaccessible to presynaptic patch-clamp recording, due to their small size.
Using improved patch-clamp techniques in brain slices, we recorded from mossy fiber terminals in the CA3 region of the hippocampus, which have a diameter of 2–5 µm.
The major steps of improvement were the enhanced visibility provided by high-numerical aperture objectives and infrared illumination, the development of vibratomes with minimal vertical blade vibrations and the use of sucrose-based solutions for storage and cutting.
Based on these improvements, we describe a protocol that allows us to routinely record from hippocampal mossy fiber boutons. Presynaptic recordings can be obtained in slices from both rats and mice.
Presynaptic recordings can be also obtained in slices from transgenic mice in which terminals are labeled with enhanced green fluorescent protein.
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