@tomr,
Neurons only use electricity to transmit information inside a neuron -- there are exceptions, some fish neurons can transmit an electrict signal directly to another neuron, but not in humans. In our brain, any info transfer between neurons goes through neurotransmitters, which are essentially hormones.
The system is extremely complex so let's not go into too much detail. You can have the basics here:
http://en.wikipedia.org/wiki/Neurotransmitter
A neuron sends an info to a synaps, which translates it into a chemichal signal emitted for a dendrite, which receives it and fires up the neuron, or inhibit it or some other effect. The connection between neurons is chemical, not electric.
The point is relevant because hormonal systems produce analog signals that can be modulated almost ad infinitum by other elements of the hormonal soup present near a synapse. These other neurotransmitters modulating the primary signal can come from the neuron sending the signal, or from another neuron controling that synaptic connection.
Classic hormonal systems that discharge within the blood stream (endocrine system) are complex, paradoxal at times, 'odd' as Fil would put it, and their outcome notoriously difficult to explain and predict. But an hormonal system of such vast complexity as the human nervous system defies all previsions and previsionists.
If it was an electric system, we would already have a pretty good idea of how it works.