IL-6

      IL-6 is secreted by astrocytes and absorbed by neurons. It is free to diffuse throughout the environment.

Secretion

      Astrocytes secrete IL-6 into the same grid space at which they are located based on the amount of IL-1B they have in storage, s. Adjusting for the astrocyte concentration parameter, q, secretion occurs as long as s is greater than

q*kd*g,
where kd is the IL-1B receptor equilibrium constant for astrocytes and g is the triggering IL-1B equilibrium factor for IL-6. The rate of secretion is the product of the IL-6 secretion rate, u, and the astrocyte concentration, q, so that
r = q u.
Because secretion occurs on the micro time scale, the increase of IL-6, DS, in the grid space of the astrocyte agent satisfies
DS = dt*q*u.
Currently, there are no limits to how much IL-6 can be in any one grid space.

Diffusion

      IL-6 diffuses according to the diffusion properties discussed above. Initially, the diffusion coefficient equals the diffusivity parameter throughout space. However, astrocyte blocking may reduce the diffusion coefficient in specific regions.


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