During the early days of neuroscience, all the non-neuronal stuff that exists in
nerve tissues was referred to as "glia," which is Greek for "glue." Such simplification
was necessary as scientists began to investigate the complex connections
and chemical signals that transpire at the synapse. More recently, the three major
cell types that occur in the glia (i.e., microglia, astrocytes, and oligodendrocytes)
have begun to receive attention for their functional roles within the multiple contexts.
The revelation that glial cells may participate in synaptic function per se is
particularly intriguing. For example, astrocytes appear to modulate neurotransmission
in nociception, and dysfunction of this role may be an important factor in
the development of pain states. Drugs that specifically affect non-neuronal cells
and thereby alter synaptic transmission have been identified, and these "glia
blockers" are helping neuroscientists to understand the role of astrocytes in the
manifestation of pain. Glia blockers not only reflect the essential participation of
non-neuronal cells to synaptic function, but may also suggest new therapeutic opportunities
for controlling neuron-neuron communication in a number of pathological conditions.
