title: Muscarinic enhancement of persistent sodium current synchronizes striatal medium spiny neurons.
abstract: Network dynamics denoted by synchronous firing of neuronal pools rely on synaptic interactions and intrinsic properties. In striatal medium spiny neurons, N-methyl-d-aspartate (NMDA) receptor activation endows neurons with nonlinear capabilities by inducing a negative-slope conductance region (NSCR) in the current-voltage relationship. Nonlinearities underlie associative learning, procedural memory, and the sequential organization of behavior in basal ganglia nuclei. The cholinergic system modulates the function of medium spiny projection neurons through the activation of muscarinic receptors, increasing the NMDA-induced NSCR. This enhancement is reflected as a change in the NMDA-induced network dynamics, making it more synchronous. Nevertheless, little is known about the contribution of intrinsic properties that promote this activity. To investigate the mechanisms underlying the cholinergic modulation of bistable behavior in the striatum, we used whole cell and calcium-imaging techniques. A persistent sodium current modulated by muscarinic receptor activation participated in the enhancement of the NSCR and the increased network synchrony. These experiments provide evidence that persistent sodium current generates bistable behavior in striatal neurons and contributes to the regulation of synchronous network activity. The neuromodulation of bistable properties could represent a cellular and network mechanism for cholinergic actions in the striatum.
authors.affiliation: Departamento de Biofísica, Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, Mexico City, Federal District 04510, Mexico.
authors.forename: Luis
authors.initials: L
authors.lastname: Carrillo-Reid
authors.forename: Fatuel
authors.initials: F
authors.lastname: Tecuapetla
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vautrelle
authors.forename: Adán
authors.initials: A
authors.lastname: Hernández
authors.forename: Ramiro
authors.initials: R
authors.lastname: Vergara
authors.forename: Elvira
authors.initials: E
authors.lastname: Galarraga
authors.forename: José
authors.initials: J
authors.lastname: Bargas
mesh_terms: D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000378:metabolism; D003342:Corpus Striatum / Q000166:cytology / Q000502:physiology*; D066298:In Vitro Techniques; D008564:Membrane Potentials; D016202:N-Methylaspartate / Q000378:metabolism; D009474:Neurons / Q000502:physiology*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D015222:Sodium Channels / Q000378:metabolism*
chemical_list: D011976:Receptors, Muscarinic; D016194:Receptors, N-Methyl-D-Aspartate; D015222:Sodium Channels; D016202:N-Methylaspartate; D012964:Sodium; D002118:Calcium