CCK Interneurons (Hippocampus)

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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)

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.

Multi-Taxonomy Classification

Taxonomy Database Cross-References

PanglaoDB Marker Cross-References

Unknown (PanglaoDB):

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

Unknown (PanglaoDB):

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

Input Patterns

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)

CCK Interneurons (Hippocampus)

CCK Interneurons (Hippocampus)

CCK Interneurons (Hippocampus)

Overview

Multi-Taxonomy Classification

Taxonomy Database Cross-References

PanglaoDB Marker Cross-References

External Database Links

Taxonomy & Classification

PanglaoDB Marker Cross-References

External Database Links

Introduction

Molecular Markers and Neurochemistry

Primary Markers

Co-expression Patterns

Morphological Diversity

Basket Cells (CCK-BCs)

Dendrite-Targeting Interneurons (CCK-DTs)

Schaffer Collateral-Associated Cells (SCAs)

Ivy Cells

Electrophysiological Properties

Synaptic Properties

Hippocampal Circuit Integration

Input Patterns

Output Targets

Role in Hippocampal Oscillations

Theta Oscillations (4-12 Hz)

Gamma Oscillations (30-100 Hz)

Sharp Wave-Ripples (100-250 Hz)

Alzheimer's Disease Involvement

Vulnerabilities

Pathological Mechanisms

Therapeutic Implications

Parkinson's Disease Relevance

Striatal Circuitry

Dyskinesias

Comparative Studies

Species Differences

Developmental Expression

Research Methods

Identification

Functional Studies

Key Publications

See Also