Christian Wilms <cwilms at stud.uni-frankfurt.de> wrote:
> If a so called "post-synaptic potential" is negative (inhibitory) or
> positive (excitatory) depends alone on the neuron, which recieves the
> signal (the so called "post-synaptic cell). The cell-membrane of this
> neuron contains ion-channels which function as receptors. If these are
> permeable for positively charged ions (Na+, K+, Ca2+), the potential
> will be excitatory, if they are negative (Cl-), the potential will be
> inhibitory. ....
> The direction an ion will move, when a channel permitting it to permeate
> is opened depends on the orientation of the driving force for this ion.
While your description is correct in most aspects, it does contain the
1) increasing the permeability for K+ will cause inhibition, and
decreasing it excitation, because the driving force for K+ is normally
such that it will flee from the cell, thus hyperpolarizing = inhibiting
2) increasing the permeability for Cl- will always cause inhibition, but
this can occur without any change in membrane potential (because of