CCK Interneurons (Hippocampus)
<table class="infobox infobox-cell">
<tr>
<th class="infobox-header" colspan="2">CCK Interneurons (Hippocampus)</th>
</tr>
<tr>
<td class="label">Taxonomy</td>
<td>ID</td>
</tr>
<tr>
<td class="label">Cell Ontology (CL)</td>
<td>[CL:0002277](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0002277)</td>
</tr>
<tr>
<td class="label">Database</td>
<td>ID</td>
</tr>
<tr>
<td class="label">Cell Ontology</td>
<td>[CL:0002277](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0002277)</td>
</tr>
<tr>
<td class="label">Marker</td>
<td>Expression</td>
</tr>
<tr>
<td class="label">CB1 cannabinoid receptor</td>
<td>High</td>
</tr>
<tr>
<td class="label">Parvalbumin</td>
<td>Subset</td>
</tr>
<tr>
<td class="label">Reelin</td>
<td>Subset</td>
</tr>
<tr>
<td class="label">NPY</td>
<td>Some subtypes</td>
</tr>
<tr>
<td class="label">Synaptic release</td>
<td>High release probability</td>
</tr>
<tr>
<td class="label">CB1 modulation</td>
<td>Presynaptic inhibition</td>
</tr>
<tr>
<td class="label">Target specificity</td>
<td>Somatic vs dendritic</td>
</tr>
<tr>
<td class="label">Unitary conductance</td>
<td>1-2 nS</td>
</tr>
<tr>
<td class="label">Approach</td>
<td>Target</td>
</tr>
<tr>
<td class="label">CCK agonists</td>
<td>CCKBR</td>
</tr>
<tr>
<td class="la
...CCK Interneurons (Hippocampus)
<table class="infobox infobox-cell">
<tr>
<th class="infobox-header" colspan="2">CCK Interneurons (Hippocampus)</th>
</tr>
<tr>
<td class="label">Taxonomy</td>
<td>ID</td>
</tr>
<tr>
<td class="label">Cell Ontology (CL)</td>
<td>[CL:0002277](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0002277)</td>
</tr>
<tr>
<td class="label">Database</td>
<td>ID</td>
</tr>
<tr>
<td class="label">Cell Ontology</td>
<td>[CL:0002277](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0002277)</td>
</tr>
<tr>
<td class="label">Marker</td>
<td>Expression</td>
</tr>
<tr>
<td class="label">CB1 cannabinoid receptor</td>
<td>High</td>
</tr>
<tr>
<td class="label">Parvalbumin</td>
<td>Subset</td>
</tr>
<tr>
<td class="label">Reelin</td>
<td>Subset</td>
</tr>
<tr>
<td class="label">NPY</td>
<td>Some subtypes</td>
</tr>
<tr>
<td class="label">Synaptic release</td>
<td>High release probability</td>
</tr>
<tr>
<td class="label">CB1 modulation</td>
<td>Presynaptic inhibition</td>
</tr>
<tr>
<td class="label">Target specificity</td>
<td>Somatic vs dendritic</td>
</tr>
<tr>
<td class="label">Unitary conductance</td>
<td>1-2 nS</td>
</tr>
<tr>
<td class="label">Approach</td>
<td>Target</td>
</tr>
<tr>
<td class="label">CCK agonists</td>
<td>CCKBR</td>
</tr>
<tr>
<td class="label">CB1 antagonists</td>
<td>Cannabinoid</td>
</tr>
<tr>
<td class="label">GABA modulation</td>
<td>GABA-A</td>
</tr>
<tr>
<td class="label">CCK gene therapy</td>
<td>CCK expression</td>
</tr>
</table>
Overview
Cck Interneurons (Hippocampus) plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.
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Multi-Taxonomy Classification
Taxonomy Database Cross-References
PanglaoDB Marker Cross-References
External Database Links
- [Cell Ontology (CL:0002277)](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0002277)
- [OBO Foundry (CL:0002277)](http://purl.obolibrary.org/obo/CL_0002277)
- [Allen Brain Cell Atlas](https://portal.brain-map.org/atlases-and-data/bkp/abc-atlas)
- [CellxGene Census](https://cellxgene.cziscience.com/)
- [Human Cell Atlas](https://www.humancellatlas.org/)
- [PanglaoDB](https://panglaodb.se/)
Taxonomy & Classification
PanglaoDB Marker Cross-References
External Database Links
- [Cell Ontology (CL:0002277)](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0002277)
- [OBO Foundry (CL:0002277)](http://purl.obolibrary.org/obo/CL_0002277)
- [Allen Brain Cell Atlas](https://portal.brain-map.org/atlases-and-data/bkp/abc-atlas)
- [CellxGene Census](https://cellxgene.cziscience.com/)
- [PanglaoDB](https://panglaodb.se/)
Introduction
Cholecystokinin (CCK)-expressing interneurons constitute a major class of inhibitory neurons in the hippocampus that play crucial roles in regulating circuit excitability, oscillatory activity, and information processing. These cells are essential for maintaining the balance between excitation and inhibition, and their dysfunction has been implicated in various neurodegenerative diseases including Alzheimer's disease and Parkinson's disease[@freund2007].
Molecular Markers and Neurochemistry
Primary Markers
CCK interneurons are defined by their expression of cholecystokinin, a peptide neurotransmitter that acts on CCK receptors (CCK-A and CCK-B subtypes)[@crawley1999]:
- CCK: The defining neuropeptide marker
- CCKAR (CCK-A receptor): Peripheral and some central expression
- CCKBR (CCK-B receptor): Predominant in the brain
- CKB: Brain-type creatine kinase
- PP: Pancreatic polypeptide (subset)
- VIP: Vasoactive intestinal peptide (subset)
Co-expression Patterns
CCK interneurons frequently co-express other neurochemical markers:
Morphological Diversity
CCK interneurons exhibit remarkable morphological heterogeneity[@somogyi2005]:
Basket Cells (CCK-BCs)
- Axonal arbors densely targeting pyramidal cell somata
- Formation of perisomatic inhibitory synapses
- Critical for controlling pyramidal neuron output
- Distinct from parvalbumin basket cells
Dendrite-Targeting Interneurons (CCK-DTs)
- Axons innervating dendritic shafts and spines
- Regulation of excitatory inputs
- Input-specific inhibition
Schaffer Collateral-Associated Cells (SCAs)
- Target dendritic spines on Schaffer collateral axons
- Feedforward inhibition
- Timing-dependent modulation
Ivy Cells
- Neuropeptide Y co-expression
- Slow-spiking properties
- Dense axonal labeling in stratum lucidum
Electrophysiological Properties
CCK interneurons display diverse firing patterns[@cauli2000]:
- Adapting firing: Progressive decrease in firing rate
- Burst-firing: Initial high-frequency burst
- Fast-spiking: Some CCK/PV co-expressing cells
- Low-threshold spiking: Subset with rebound properties
Synaptic Properties
Hippocampal Circuit Integration
CCK interneurons receive diverse synaptic inputs:
- Local collaterals: From CA3 and CA1 pyramidal neurons
- Feedback inhibition: Reciprocal connections
- Subcortical inputs: From septum and brainstem
- Chandelier cell inputs: Interneuron-specific
Output Targets
- CA1/CA3 pyramidal neuron somata: Basket cells
- Dendritic shafts: Dendrite-targeting cells
- Other interneurons: Disinhibitory circuits
- Extrinsic targets: Entorhinal cortex, subiculum
Role in Hippocampal Oscillations
Theta Oscillations (4-12 Hz)
CCK interneurons contribute to theta rhythm generation and modulation[@klausberger2003]:
- Phase-locked firing during theta
- Entrainment of pyramidal neuron timing
- Coordination of burst firing
- Spatial navigation support
Gamma Oscillations (30-100 Hz)
CCK basket cells are crucial for gamma generation:
- Synchronization of pyramidal cells
- PING (pyramidal-interneuron gamma) mechanism
- ASSEMBLY (interneuron network gamma)
- Cognitive processing facilitation
Sharp Wave-Ripples (100-250 Hz)
- CCK interneuron silencing during ripples
- Ripple initiation mechanisms
- Memory consolidation support
Alzheimer's Disease Involvement
Vulnerabilities
CCK interneurons show specific vulnerabilities in AD[@palop2010]:
- Amyloid-beta toxicity: Direct effects on CCK neurons
- Early dysfunction: Precedes plaque formation
- Network hyperexcitability: Loss of somatic inhibition
- Circuit remodeling: Compensatory changes
Pathological Mechanisms
Amyloid-beta effects:
- Reduced CCK expression
- Impaired GABA release
- Synaptic dysfunction
Tau pathology:
- Neuronal loss in CCK populations
- Connectivity disruption
Network dysfunction:
- Hyperexcitability
- Seizure susceptibility
- Memory circuit impairment
Therapeutic Implications
Parkinson's Disease Relevance
Striatal Circuitry
CCK signaling modulates striatal function[@gong1999]:
- [Dopamine](/mechanisms/dopaminergic-signaling)CCK interactions
- Motor control modulation
- L-DOPA response
Dyskinesias
- CCK involvement in L-DOPA-induced dyskinesias
- CCK antagonist potential
Comparative Studies
Species Differences
- Rodent CCK distribution well characterized
- Primate studies reveal additional populations
- Human hippocampal CCK chemistry being mapped
Developmental Expression
- CCK expression develops postnatally
- Critical periods for circuit formation
- Experience-dependent plasticity
Research Methods
Identification
- CCK-Cre driver lines
- CCK immunostaining
- In situ hybridization
- Reporter mice
Functional Studies
- Optogenetic manipulation
- Chemogenetic silencing/activation
- Patch-clamp electrophysiology
- Calcium imaging
Key Publications
[Freund TF, Katona I. Perisomatic inhibition. Neuron. 2007](https://doi.org/10.1016/j.neuron.2007.09.012)
[Bartos M, et al. Synaptic mechanisms of synchronized gamma oscillations. Nat Rev Neurosci. 2007](https://doi.org/10.1038/nrn2194)
[Palop JJ, Mucke L. Epilepsy and hyperexcitability in Alzheimer's disease. Nat Neurosci. 2010](https://doi.org/10.1038/nm.2654)
[Klausberger T, Somogyi P. Neuronal diversity and temporal dynamics. Science. 2008](https://doi.org/10.1126/science.1149381)
[Cossart R. The maturation of cortical interneuron diversity. Nat Neurosci. 2014](https://doi.org/10.1038/nn.3634)See Also
- [CA1 Pyramidal Neurons
- [Parvalbumin Interneurons](/cell-types/parvalbumin-interneurons)
- Hippocampal Interneurons](/cell-types/ca1-pyramidal-neurons
--parvalbumin-interneurons
--hippocampal-interneurons)
- [Alzheimer Disease](/diseases/alzheimers-disease)
- [GABA Signaling
- CCK Signaling
](/mechanisms/gaba-signaling
--cck-signaling)##