Table 3

Model Kinetics and Rate Constant Values.

Abbreviation

Description

Default Values


kcrh

Rate constant for generation of CRH

3.8 × 10-1

kacth

Rate constant for generation of ACTH

1.085 × 10-1

kcor

Rate constant for generation of cortisol

2.4 × 10-3

kcdeg

Rate constant for the degradation of cortisol.

8.5 × 10-3

Vcrh

Saturation level of inhibition for hypothalamic cells

1

Vacth

Saturation level of inhibition for pituitary secretory cells

1

kda

Dissociation constant for cortisol in the hypothalamus

50

kdc

Dissociation constant for cortisol in the pituitary

50

kgr

Concentration of cortisol at which GR receptors are 50% saturated.

1 × 108

kmr

Concentration of cortisol at which MR is 50% of its max

2.5 × 103

kmad

Rate constant for the deactivation of MR receptors

1

knon

Rate constant for the inhibition of CA1 neurons by MR receptors.

4.99 × 10-2

kGRD

Rate constant for degradation of GR activity

4.45 × 10-1

kngf

Rate constant for stimulation of CA1 neurons by growth factors.

10 × 10-8

knps

Rate constant for death of neurons.

4.5 × 10-2

kngfs

Rate constant for neuronal growth factor decline.

1

knbd

Rate constant for stimulation of NBD

5 × 10-2

kses

Rate constant for stimulation of synaptic excitatory signals.

1.049

ksf

Rate constant for stimulation of synaptic firing

1.049

kso

Rate constant for stimulation of synaptic output.

1.049

kho

Rate constant for stimulation of hippocampal output.

1.049

khos

Rate constant for degradation of synaptic output

5.5 × 104

kSI

Rate constant for inhibition of synaptic firing by synaptic inhibitory signals.

2.2 × 10-1

kSGR

Rate constant for production of synaptic inhibitory signals.

4.45 × 10-1

ksos

Rate constant for stimulation of synaptic firing.

1.049

ksisd

Rate constant for decline in synaptic inhibitory signals

3.8 × 10-1

Vcrh

Saturation level of inhibition for hypothalamic cells

1

Vacth

Saturation level of inhibition for pituitary cells

1

VmaxMRA

Maximum rate of activity of MR receptors

1 × 102

VmaxGRA

Maximum rate of activity of GR receptors

1 × 102

Ngr

Hill coefficient for GR receptor Activity

3.6

Nmr

Hill coefficient for MR receptor activity

5.8

HV

Volume of Hippocampus

100


This table describes the rate constant expressions used to define the interaction between variables within the model. Rate constants were extrapolated and simplified from known biophysical and biochemical reactions within hippocampal and HPA tissues. Michalelis-Menton steady state enzyme substrate reactions and the Hill receptor-ligand binding equations were used to define interactions between model variables.

McAuley et al. BMC Neuroscience 2009 10:26   doi:10.1186/1471-2202-10-26

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