Alpha2A-adrenoceptors strengthen working memory networks by inhibiting cAMP-HCN channel signaling in prefrontal cortex.
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.
Wang
Min
M
Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06510 USA.
Ramos
Brian P
BP
Paspalas
Constantinos D
CD
Shu
Yousheng
Y
Simen
Arthur
A
Duque
Alvaro
A
Vijayraghavan
Susheel
S
Brennan
Avis
A
Dudley
Anne
A
Nou
Eric
E
Mazer
James A
JA
McCormick
David A
DA
Arnsten
Amy F T
AF
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D054815:Cyclic Nucleotide-Gated Cation Channels; D049229:Dendritic Spines / Q000737:chemistry / Q000648:ultrastructure; D004594:Electrophysiology; D016316:Guanfacine / Q000494:pharmacology; D007473:Ion Channels / Q000032:analysis / Q000502:physiology*; D008253:Macaca mulatta; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009474:Neurons / Q000737:chemistry / Q000502:physiology*; D017397:Prefrontal Cortex / Q000166:cytology / Q000502:physiology*; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018341:Receptors, Adrenergic, alpha-2 / Q000032:analysis / Q000502:physiology*
D000316:Adrenergic alpha-Agonists; D054815:Cyclic Nucleotide-Gated Cation Channels; D007473:Ion Channels; D011743:Pyrimidines; D018341:Receptors, Adrenergic, alpha-2; C082246:ICI D2788; D016316:Guanfacine; D000242:Cyclic AMP