Base Class for Glutamate synapse with NMDA and AMPA channels.
This is a slow version of a glutamate-synapse. NMDA and AMPA channels are conductance based Attention: Neuron needs biological resting potential (ca. -70mV). Note that this synapse can not be used as an inhibitory synapse! Since channels are conductance based, weight has to be much larger (about 50x)