The Dynamic Neuron, by John
Smythies, is an important review and survey of the biochemistry literature on
the neurochemical basis of synaptic plasticity. Smythies is the Director of the Division of Neurochemistry, UC
San Diego; Senior Research Fellow, Institute of Neurology, Queen Square London;
and visiting Professor, Department of Psychiatry, Harvard Medical School.

Synaptic plasticity is a dramatic
paradigm shift from the days of high school biology. The synapses between neurons and overall neuronal structure were
relatively fixed. Learning and other
mental processes relied on the existing network by adjusting the threshold and
firing rate between the synapses. And
within the cell, proteins and other biochemical miscellanea drift around as in
a soup managing to serendipitously interact, enabling the cell to function
quite nicely. Our current knowledge
about synaptic plasticity paints an entirely different picture. A cell from the inside is highly structured
and functions more like a collection of coordinated mini-factories that would
make a production manager envious. And
the synapses are much more frequently replaced, deleted, and built anew. They do not die, like a branch withering on
a tree. They are actively dismantled
and assembled, enabling new connections and ridding the brain of underused
connections.

The book divides itself into
chapters relevant to representing the complexity of the biochemical processes
underwriting synaptic plasticity. 
Chapter Two explains the biochemical mechanisms involved in endocytosis
and exocytosis. Endocytosis, the process in which a substance gains entry into a cell
without passing through the cell membrane, is implicated, among other things,
in the growth of spines, desensitization of the receptor, and repair of
oxidatively damaged proteins.  
Exocytosis is the process in which neurotransmitters are released from
the cell. Chapter Three, “Special
Proteins,” focuses on the proteins involved in neuritic growth and in how cells
or cell bits adhere to each other and break apart. Chapter Four, aptly titled “Miscellaneous Items,” covers the
loose odds and ends surrounding the biochemistry of synaptic plasticity.  The last chapter, “Pharmacological
Implications and Clinical Applications,” lays emphasis on schizophrenia and Alzheimer’s disease with respect to
details previously discussed.

The Dynamic Neuron is High
Science. It is not for the scientific
hobbyists.  It is intended for someone actively engaged in biochemistry or
neuroscience research wanting a concise review of the current scientific
literature on synaptic plasticity. The
biochemistry involved is exceedingly complex. 
Paragraph after paragraph reads like the following passage, haphazardly
chosen, from Chapter Two; “[t]he beta adrenergic receptor is rapidly
endocytosed whereas the vasopressin receptor is rapidly endocytosed, both by a
clathrin-beta-arrestin mechanism.” If you found that sentence impenetrable, the
book will be too.

 © 2002 James Hitt

James
Hitt is a Ph.D. candidate in philosophy at the Graduate School and
University Center, City University of New York.

Categories: General