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In this context, it is less important that Langley excluded the striated part of the
oesophagus from his definition of the enteric nervous system (ENS). Much more
remarkable seems to be that for Langley, a physiologist, structural reasonswere the
most decisive for taking the nervous system within the wall of the gastrointestinal
tract as an entity unto itself. On the one hand, he argued that enteric nerve
cells differ in their histological character from those in para- and prevertebral
ganglia. On the other hand, there were few connections of enteric nerve plexuses
with the central nervous system (CNS) through sympathetic or other autonomic
nerves (which had already been described, however; Auerbach 1862). In his later,
more famous monograph, he divided the autonomic nerves into three groups:
sympathetic, parasympathetic and intestinal nerves (Langley 1921).
This division seems to be all the more modern considering that, during the
following decades, many authors and textbooks moved away from this division.
The significance of enteric neurons was reduced to that of postganglionic relay
stations of vegetative nerves (Müller 1921; Lawrentjew 1929; Botár et al. 1942). In
retrospect, this reduction is, amongst other things, even more surprising because
functional as well as structural characteristics of the ENS, already partly known
at that time, indicated a considerable autonomous character of gut functions. This
autonomous character had by all means been identified with the intrinsic nerves
(Bayliss and Starling 1899; Trendelenburg 1917).
In the 1970s, decades of stagnation of scientific research in this field came to an
end. In particular, the introduction of immunohistochemistry revealed a (chemical)
variety of enteric neurons which is unequalled in the remaining peripheral
nervous system. The first monograph in this field carried the same title Langley
used for this part of the nervous system in 1900: ‘The enteric nervous system’
(Furness and Costa 1987). Amore up-to-date monograph is that of Furness (2006). |
