A mathematical model of potential spreading along neuron dendrites is
proposed to describe the synaptic transmissions in the so-called cereb
ellar granule cells, which consist of a nearly spherical soma emitting
a finite number of dendrites. The model accounts for the nonlinear de
pendence of the NMDA receptors, located at the virtual ends of any den
drite, upon the voltage. The corresponding initial-boundary value prob
lem is formulated in the framework of Sobolev spaces. Existence and un
iqueness of a weak solution are proved along with regularity results e
nsuring that the solution is classical.