Axonal sorting of Kir3.3 defines a GABA-containing neuron in the CA3 region of rodent hippocampus

Gisela Grosse, Dirk Eulitz, Theodor Thiele, Ingrid Pahner, Sascha Schröter, Shigeo Takamori, Johannes Grosse, Kevin Wickman, Rosemarie Tapp, Rüdiger W. Veh, Ole Petter Ottersen, Gudrun Ahnert-Hilger

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Hippocampal interneurons comprise a heterogeneous group of locally acting GABAergic neurons. In addition to their variability in cotransmitter content and receptor profile, they express a variety of potassium channels that specify their individual properties. Here we describe a new type of large GABA-containing neuron in rodent hippocampus that is characterized by an axonal sorting of the potassium channel Kir3.3. The parent cell bodies of the Kir3.3-positive axons are located in CA3, as assessed by primary cultures derived from hippocampal subareas. At postnatal day 14 these neurons appear at the border between stratum oriens and stratum pyramidale of CA3, from where their axons pass through stratum pyramidale to join the mossy fiber tract. In adult hippocampus, high levels of Kir3.3 channel protein exist in axons that run with the mossy fiber tract. Kir3.3 and the vesicular GABA transporter could be identified in subpopulations of large synaptic terminals that probably derive from Kir3.3 neurons. Axonal sorting of Kir3.3 appears to be typical of a group of large inhibitory neurons, including Purkinje cells and a novel type of interneuron in CA3. Kir3.3 neurons might modulate the activity of CA3 circuitries and consequently memory processing in the hippocampus.

Original languageEnglish (US)
Pages (from-to)709-724
Number of pages16
JournalMolecular and Cellular Neuroscience
Issue number3
StatePublished - Nov 2003

Bibliographical note

Funding Information:
The authors are indebted to Evelyn Heuckendorf, Annemarie Löchner, and Ina Wolter for outstanding technical assistance and Dr. Andreas Draguhn for helpful comments. The work was supported by the Deutsche Forschungsgemeinschaft and the Stiftung Verum.


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