| A gradual increase in membrane resistance is critical to reduced fluctuation-based modulation of input-output responses in an eLlF model | We found that a AT value of 15 mV best matched experimental values of steady-state membrane input resistance observed in stellate cells (Fig 3B). |
| Electrophysiology | Stellate cell identity was established using the following criteria: 1) presence of a hyperpolar-ization-mediated membrane voltage sag, 2) impedance and resonance measures indicating a steady-state input resistance at rest between 35 MS) and 80 MS) and the presence of a ~5 HZ resonance peak determined using methods described previously [49] and 3) the location and cell morphology under DIC-IR optics (i.e. |
| Reducing voltage-dependence of membrane resistance reduces fluctuation-based modulation of input-output curves in stellate cells | Previous work in other neurons has established that steady-state Na+ conductance, mediated either by a window current or persistent Na+ conductance, can substantially increase membrane resistance with depolarization [26,41]. |
| Stellate cells express significant non-linear membrane properties leading up to spike threshold | Depolarizing stellate cells led to a progressive increase in steady-state membrane input resistance (Fig 2A; one-way ANOVA, P <0.001, n = 12). |
| a co g-n —stellate v,, trajectory | (A) Average steady-state input resistance as a function of membrane voltage. |
| Abstract | The computation of all feasible metabolic routes with these models, given stoichiometric, thermodynamic, and steady-state constraints, provides important insights into the metabolic capacities of a cell. |
| Characterization of the optimal solution space: Illustration with a toy model | The resulting FBA is formulated as the linear program: where N] = 0 is the steady-state constraint with N as stoichiometric matrix and I as flux vector (or flux pathway). |
| Flux balance analysis | By using a linear programming approach, FBA can optimize (maximize or minimize) an objective function subject to the steady-state constraint, thermodynamic constraints, and capacity constraints: |
| Flux balance analysis | Next, N I = 0 is the steady-state constraint. |
| Dissecting enzyme catalysis: assessing the impact of reaction molecularity | It would be interesting to derive similar relations under non-equilibrium steady-state conditions, provided that biological systems operate in this regime. |
| E-glc-atp | The reference steady-state flux under this condition was set to the experimental value of 0.064 mM/min found in the literature [48]. |
| Parameterization and sampling of the catalytic mechanism | To overcome this limitation, normalization of all the variables around a reference point ( steady-state flux) is a convenient strategy. |
| Parameterization and sampling of the catalytic mechanism | Using a sampled set of reversibilities satisfying Equation 11 and imposing the steady-state condition on each elementary reaction, 1'. |