Plasticity of burst firing induced by synergistic activation of metabotropic glutamate and acetylcholine receptors.
Subiculum, the primary efferent pathway of hippocampus, participates in memory for spatial tasks, relapse to drug abuse, and temporal lobe seizures. Subicular pyramidal neurons exhibit low-threshold burst firing driven by a spike afterdepolarization. Here we report that burst firing can be regulated by stimulation of afferent projections to subiculum. Unlike synaptic plasticity, burst plasticity did not require synaptic depolarization, activation of AMPA or NMDA receptors, or action potential firing. Rather, enhancement of burst firing required synergistic activation of group I, subtype 1 metabotropic glutamate receptors (mGluRs) and muscarinic acetylcholine receptors (mAChR). When either of these receptors was blocked, a suppression of bursting was revealed, which in turn was blocked by antagonists of group I, subtype 5 mGluRs. These results indicate that the output of subiculum can be strongly and bidirectionally regulated by activation of glutamatergic inputs within the hippocampus and cholinergic afferents from the medial septum.
Moore
Shannon J
SJ
Department of Neurobiology and Physiology, Northwestern University, 2205 Tech Drive, Evanston, IL 60208, USA.
Cooper
Donald C
DC
Spruston
Nelson
N
D000109:Acetylcholine / Q000378:metabolism; D000200:Action Potentials / Q000502:physiology; D000344:Afferent Pathways / Q000166:cytology / Q000378:metabolism; D000818:Animals; D002799:Cholinergic Fibers / Q000378:metabolism; D004558:Electric Stimulation; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism*; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D017966:Pyramidal Cells / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011950:Receptors, Cholinergic / Q000187:drug effects / Q000378:metabolism*; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism; D012686:Septal Nuclei / Q000166:cytology / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D013826:Theta Rhythm
D018691:Excitatory Amino Acid Antagonists; D011950:Receptors, Cholinergic; D018094:Receptors, Metabotropic Glutamate; D011976:Receptors, Muscarinic; C104077:metabotropic glutamate receptor type 1; D018698:Glutamic Acid; D000109:Acetylcholine