Commun Nonlinear Sci Numer Simulat 32 (2016) 262–272 Contents lists available at ScienceDirect Commun Nonlinear Sci Numer Simulat journal homepage: www.elsevier.com/locate/cnsns Effect of calcium channel noise in astrocytes on neuronal transmission Jun Tang a,∗ , Tong-Bo Liu a , Jun Ma b , Jin-Ming Luo a , Xian-Qing Yang a a College of Science, China University of Mining and Technology, Xuzhou 221116, China b Department of Physics, Lanzhou University of Technology, Lanzhou 730050, China article info Article history: Received 15 May 2015 Revised 25 July 2015 Accepted 21 August 2015 Available online 28 August 2015 Keywords: Astrocyte Neuron information transmission Noise abstract In this study, a Langevin model is constructed by modifying a neuron–astrocyte coupled model that comprises a pyramidal neuron, an interneuron, and an astrocyte. This Langevin model considers random open-close transitions of calcium ion channels in the endoplasmic reticu- lum membrane of astrocytes. The effect of noise in the astrocytes on neuronal transmission is investigated numerically based on a random model under both normal and overexpression conditions of metabotropic glutamate receptors on astrocyte membranes. This study suggests that noise could change the firing patterns of two neurons during neuronal information trans- mission. Noise facilitates the occurrence of episodic spikes (ESs) in both neurons. However, the noise-induced ESs occur irregularly, compared with ESs in a deterministic model, and the change in regularity with noise exhibits the coherence- resonance phenomenon. Furthermore, synchronicity between noisy ESs in two neurons depends significantly on various parameters. ESs completely occur synchronously but irregularly in certain parameter regions, whereas ESs in other parameter values are antiphase synchronous. This study implies not only that the cal- cium dynamics in astrocytes could participate in neuronal transmission, but also that noise in astrocytes may be transferred to neurons and may affect synaptic transmission significantly. © 2015 Elsevier B.V. All rights reserved. 1. Introduction As the major subtype of glial cells in the brain, astrocyte cells are traditionally considered as non-excitable support cells of neuron systems because these cells cannot generate action potentials (APs). Over the past decades, astrocytes have been found to participate in synaptic transmission by modulating and responding to the release of neurotransmitters [1–3]. Astrocytic pro- cesses are often opposed to synaptic junctions. These processes allow astrocytes to “listen and communicate” with neurons, thereby generating the “tripartite synapse” notion that consists of a presynaptic neuron, an astrocyte, and a postsynaptic neuron [4]. The fire of the presynaptic neuron facilitates the release of neurotransmitters, such as glutamate. Released glutamates then diffuse and bind to metabotropic glutamate (mGlu) receptors on the membrane of adjacent astrocytes. The activation of mGlu receptors triggers a complex pathway that augments inositol 1, 4, 5-triphosphate (IP 3 ) in astrocytes and increases intra-astrocytic Ca 2+ concentration. Calcium elevation causes a release of glutamates from an astrocyte to the synaptic cleft. The released glu- tamates can bind mGlu receptors on the presynaptic membrane and/or NMDA receptors on the postsynaptic side, thus synaptic transmission is modulated [5–8]. In fact, the calcium elevation can also result in the release of other neurotransmitters, such as Adenosine Triphosphate (ATP), which enhances the neuronal excitability [9–12]. ∗ Corresponding author. E-mail address: tjuns1979@126.com (J. Tang). http://dx.doi.org/10.1016/j.cnsns.2015.08.019 1007-5704/© 2015 Elsevier B.V. All rights reserved.