Adaptive Mossy Cell Circuit Plasticity after Status Epilepticus. 2022

Corwin R Butler, and Gary L Westbrook, and Eric Schnell
Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon 97239.

Hilar mossy cells regulate network function in the hippocampus through both direct excitation and di-synaptic inhibition of dentate granule cells (DGCs). Substantial mossy cell loss accompanies hippocampal circuit changes in epilepsy. We examined the contribution of surviving mossy cells to network activity in the reorganized dentate gyrus after pilocarpine-induced status epilepticus (SE). To examine functional circuit changes, we optogenetically stimulated mossy cells in acute hippocampal slices from male mice. In control mice, activation of mossy cells produced monosynaptic excitatory and di-synaptic GABAergic currents in DGCs. In pilocarpine-treated mice, mossy cell density and excitation of DGCs were reduced in parallel, with only a minimal reduction in feedforward inhibition, enhancing the inhibition/excitation ratio. Surprisingly, mossy cell-driven excitation of parvalbumin-positive (PV+) basket cells, primary mediators of feed-forward inhibition, was maintained. Our results suggest that mossy cell outputs reorganize following seizures, increasing their net inhibitory effect in the hippocampus.SIGNIFICANCE STATEMENT Hilar mossy cell loss in epilepsy is associated with hippocampal hyperexcitability, potentially as a result of disrupted dentate microcircuit function. We used transgenic mice, translational mouse modeling, viral vectors, and optogenetics to selectively examine functional changes to mossy cell outputs following status epilepticus (SE). Interestingly, the outputs of surviving mossy cells exhibited adaptive plasticity onto target parvalbumin-positive (PV+) interneurons, resulting in a relative increase in their inhibitory control of dentate granule cells (DGCs). Our findings suggest that residual mossy cell outputs can reorganize in a homeostatic manner, which may provide clues for therapeutic targeting of this microcircuit.

UI MeSH Term Description Entries
D008297 Male Males
D010320 Parvalbumins Low molecular weight, calcium binding muscle proteins. Their physiological function is possibly related to the contractile process. Parvalbumin,Parvalbumin B
D010862 Pilocarpine A slowly hydrolyzed muscarinic agonist with no nicotinic effects. Pilocarpine is used as a miotic and in the treatment of glaucoma. Isopilocarpine,Isoptocarpine,Ocusert,Pilocarpine Hydrochloride,Pilocarpine Mononitrate, (3S-cis)-Isomer,Pilocarpine Nitrate,Pilocarpine, Monohydrochloride, (3S-cis)-Isomer,Salagen,Hydrochloride, Pilocarpine,Nitrate, Pilocarpine
D000222 Adaptation, Physiological The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT. Adaptation, Physiologic,Adaptations, Physiologic,Adaptations, Physiological,Adaptive Plasticity,Phenotypic Plasticity,Physiological Adaptation,Physiologic Adaptation,Physiologic Adaptations,Physiological Adaptations,Plasticity, Adaptive,Plasticity, Phenotypic
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D013226 Status Epilepticus A prolonged seizure or seizures repeated frequently enough to prevent recovery between episodes occurring over a period of 20-30 minutes. The most common subtype is generalized tonic-clonic status epilepticus, a potentially fatal condition associated with neuronal injury and respiratory and metabolic dysfunction. Nonconvulsive forms include petit mal status and complex partial status, which may manifest as behavioral disturbances. Simple partial status epilepticus consists of persistent motor, sensory, or autonomic seizures that do not impair cognition (see also EPILEPSIA PARTIALIS CONTINUA). Subclinical status epilepticus generally refers to seizures occurring in an unresponsive or comatose individual in the absence of overt signs of seizure activity. (From N Engl J Med 1998 Apr 2;338(14):970-6; Neurologia 1997 Dec;12 Suppl 6:25-30) Absence Status,Complex Partial Status Epilepticus,Generalized Convulsive Status Epilepticus,Non-Convulsive Status Epilepticus,Petit Mal Status,Simple Partial Status Epilepticus,Grand Mal Status Epilepticus,Status Epilepticus, Complex Partial,Status Epilepticus, Electrographic,Status Epilepticus, Generalized,Status Epilepticus, Generalized Convulsive,Status Epilepticus, Grand Mal,Status Epilepticus, Non-Convulsive,Status Epilepticus, Simple Partial,Status Epilepticus, Subclinical,Electrographic Status Epilepticus,Generalized Status Epilepticus,Non Convulsive Status Epilepticus,Status Epilepticus, Non Convulsive,Status, Absence,Status, Petit Mal,Subclinical Status Epilepticus
D051379 Mice The common name for the genus Mus. Mice, House,Mus,Mus musculus,Mice, Laboratory,Mouse,Mouse, House,Mouse, Laboratory,Mouse, Swiss,Mus domesticus,Mus musculus domesticus,Swiss Mice,House Mice,House Mouse,Laboratory Mice,Laboratory Mouse,Mice, Swiss,Swiss Mouse,domesticus, Mus musculus
D018891 Dentate Gyrus GRAY MATTER situated above the GYRUS HIPPOCAMPI. It is composed of three layers. The molecular layer is continuous with the HIPPOCAMPUS in the hippocampal fissure. The granular layer consists of closely arranged spherical or oval neurons, called GRANULE CELLS, whose AXONS pass through the polymorphic layer ending on the DENDRITES of PYRAMIDAL CELLS in the hippocampus. Dentate Fascia,Fascia Dentata,Gyrus Dentatus,Area Dentata,CA4 Field of Hippocampal Formation,CA4 Region, Hippocampal,CA4 of Lorente de No,Cornu Ammonis 4 Area,Hilus Gyri Dentati,Hilus of Dentate Gyrus,Hilus of the Fascia Dentata,Hippocampal CA4 Field,Hippocampal Sector CA4,Area Dentatas,CA4 Field, Hippocampal,CA4, Hippocampal Sector,Dentata, Area,Dentata, Fascia,Dentatas, Area,Fascia, Dentate,Field, Hippocampal CA4,Gyrus, Dentate,Hippocampal CA4 Region,Region, Hippocampal CA4,Sector CA4, Hippocampal
D019599 Mossy Fibers, Hippocampal Axons of certain cells in the DENTATE GYRUS. They project to the polymorphic layer of the dentate gyrus and to the proximal dendrites of PYRAMIDAL CELLS of the HIPPOCAMPUS. These mossy fibers should not be confused with mossy fibers that are cerebellar afferents (see NERVE FIBERS). Hippocampal Mossy Fibers,Hippocampal Mossy Fiber,Mossy Fiber, Hippocampal

Related Publications

Corwin R Butler, and Gary L Westbrook, and Eric Schnell
December 2003, The Journal of neuroscience : the official journal of the Society for Neuroscience,
Corwin R Butler, and Gary L Westbrook, and Eric Schnell
February 2011, Epilepsy research,
Corwin R Butler, and Gary L Westbrook, and Eric Schnell
October 2000, Annals of neurology,
Corwin R Butler, and Gary L Westbrook, and Eric Schnell
July 2019, Molecular neurobiology,
Corwin R Butler, and Gary L Westbrook, and Eric Schnell
February 1995, The Journal of comparative neurology,
Corwin R Butler, and Gary L Westbrook, and Eric Schnell
January 2022, Experimental neurology,
Corwin R Butler, and Gary L Westbrook, and Eric Schnell
February 1994, Archives of neurology,
Corwin R Butler, and Gary L Westbrook, and Eric Schnell
May 2001, Stroke,
Copied contents to your clipboard!