Page 1 of 1
difference between <-> and << ?
Posted: Sun Sep 30, 2007 8:22 pm
by xyang
Hi, How are you?
I read from NEURON book about chemical reaction and understant the equation (page 238):
~ cai + pump <-> capump (k1, k2)
However, I also saw sodium diffusion in Dr. Canavier's paper (1999) as:
~ nai << (-ina/(FARADAY)*PI*diam*(1e4))
Where can I find the explanation for the symbol "<<"
Thank you!
Have a great day!
Xianghong
Re: difference between <-> and << ?
Posted: Mon Oct 01, 2007 10:57 am
by ted
xyang wrote:Where can I find the explanation for the symbol "<<"
Symbols are listed in the Index. On page 413, the first page of the Index, you will find
Code: Select all
<< (explicit flux) -- see KINETIC block: << (explicit flux)
KINETIC block terms are referenced on page 435, where you will find
Code: Select all
KINETIC block . . .
. . .
<< (explicit flux) 253
The paragraph on the bottom of page 253 discusses this statement
Code: Select all
~ ca[0] << (-ica*PI*diam/(2*FARADAY)) : ica is Ca efflux
from a calcium accumulation mechanism. Quoting from that paragraph:
[ this statement ] is equivalent to a differential equation that describes the
contribution of transmembrane calcium current to Ca2+ in the outermost
shell. The << signifies an explicit flux.
In other words, calcium current is a flux of calcium ions that leaves or
enters the cytoplasm that is just inside the cell membrane.
thank you
Posted: Mon Oct 01, 2007 11:27 am
by xyang
Hi, Ted:
Thank you for the explanation! This is very clear and helpful!
Best regards,
Xianghong