The ultrastructure of Auerbach's plexus in the guinea-pig. I. Neuronal elements

Abstract

The ultrastructural features of nerve cell bodies and axon profiles within Auerbach's plexus in the stomach, ileum, caecum and colon of the guinea-pig have been examined. Nerve cell bodies have been tentatively classified into nine different types according to their size, distribution of organelles, location and relationship to satellite cells. Except for cell size, no attempt has been made to correlate ultrastructual with light microscopical observations. On the basis of vesicular size, shape and content, eight morphologically distinct types of axon profile have been identified as well as two profile types which are thought to reflect different physiological conditions. The axons contained various populations of small, mostly granular vesicles; small, round agranular vesicles; small, flattened vesicles; large flattened or elongated vesicles; and three types of large vesicle with granular contents distinguished by size. Some correlation between types of axon profile and two types of nerve cell body was recognized. However, more than one type of axon profile usually formed synapses with one type of cell body, and a precise correlation was not determined.

Morphology and serotonergic innervation of physiologically identified cells of the guinea pig's myenteric plexus

“…There are more than a dozen established or putative neurotransmitters (Furness and Costa, 1982b), and electron microscopy has been used to identify at least eight different neuronal classes (Cook and Burnstock, 1976). Extracellular recording has led to the description of six patterns of neuronal activity (Wood, 1981).…”

“…Radioautography The dense HRP reaction product tended to obscure these specializations, and they are rare and rudimentary, in any case, in the ENS (Baumgarten et al, 1970;Cook and Burnstock, 1976;Manber and Gershon, 1979) (current reccrd on lower trace) induces action potentials followed by an AH. Current pulses injected during the AH fail to elicit action potentials.…”

Ultrastructure of intramural ganglia in the striated muscle portions of the guinea pig oesophagus

“…Varicosities containing numerous elongated structures resembling those found in the guinea pig caecum ( fig. 25 in Cook & Burnstock, 1976) were very occasionally seen. However, axon varicosities characterised by small granular vesicles and by heterogeneous populations of vesicles (Baumgarten et al 1970) were not found.…”

Autonomic Neurotransmission: 60 Years Since Sir Henry Dale

“…The precise combinations of neurotransmitters (and neuromodulators) contained in individual neurons and their projections and central connections, termed their chemical coding, have been defined in studies of the enteric nervous system (28). Ultrastructural studies of the enteric nervous system offered the first suggestion that there were several different cotransmitters in autonomic nerves; at least nine distinguishable types of axon profiles showing different combinations of vesicle types were described in the guinea pig myenteric plexus (29).…”