Alpha2a-adrenoceptors Strengthen Working Memory Networks by Inhibiting Camp-hcn Channel Signaling in Prefrontal Cortex.
From: Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06510 USA.
Cell
- Publish Date: Apr 2007
- ISSN: 0092-8674
- Volume: 129
- Issue: 2
- Pages: 397-410
- Medium: Print
- Language: English
- Citation (JAMA): Wang Min, Ramos Brian P, Paspalas Constantinos D, et al. Alpha2a-adrenoceptors Strengthen Working Memory Networks by Inhibiting Camp-hcn Channel Signaling in Prefrontal Cortex.. Cell Apr 2007;129:397-410
Abstract
Spatial working memory (WM; i.e., “scratchpad” memory) is constantly updated to guide behavior based on representational knowledge of spatial position. It is maintained by spatially tuned, recurrent excitation within networks of prefrontal cortical (PFC) neurons, evident during delay periods in WM tasks. Stimulation of postsynaptic alpha2A adrenoceptors (alpha2A-ARs) is critical for WM. We report that alpha2A-AR stimulation strengthens WM through inhibition of cAMP, closing Hyperpolarization-activated Cyclic Nucleotide-gated (HCN) channels and strengthening the functional connectivity of PFC networks. Ultrastructurally, HCN channels and alpha2A-ARs were colocalized in dendritic spines in PFC. In electrophysiological studies, either alpha2A-AR stimulation, cAMP inhibition or HCN channel blockade enhanced spatially tuned delay-related firing of PFC neurons. Conversely, delay-related network firing collapsed under conditions of excessive cAMP. In behavioral studies, either blockade or knockdown of HCN1 channels in PFC improved WM performance. These data reveal a powerful mechanism for rapidly altering the strength of WM networks in PFC.
Mesh Headings (Keywords): Adrenergic alpha-Agonists, Animals, Cyclic AMP, Cyclic Nucleotide-Gated Cation Channels, Dendritic Spines, Electrophysiology, Guanfacine, Ion Channels, Macaca mulatta, Male, Memory, Short-Term, Neurons, Prefrontal Cortex, Pyrimidines, Rats, Rats, Sprague-Dawley, Receptors, Adrenergic, alpha-2
Check for Full Text / PubMed Unique Identifier (PMID): 17448997
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