[Horseradish peroxidase localization of the cell bodies of the sympathetic and parasympathetic neurones controlling the lower oesophageal sphincter in the cat (author's transl)].

The localization of the parasympathetic preganglionic and sympathetic postganglionic neuronal cell bodies innervating the lower oesophageal sphincter (l.o.s.) has been investigated in cats, using the technique of horseradish peroxidase (HRP) retrograde axonal transport. HRP was injected into the sphincteric muscle layers (under aseptic conditions). The animals were sacrificed 72 hours later and fixed by perfusion via the aorta. The medulla oblongata and the sympathetic chains from the stellate to T12 ganglia were removed and processed for HRP identification. 1. Labelled cell bodies were identified in the medulla, the stellate and other thoracic ganglia and in the caeliac ganglia. 2. In the medulla, the labelled neurones were located mainly in the vagal dorsal motor nucleus and, to a lesser extent, in the nucleus ambiguus. A few cell bodies were observed between both nuclei. The medullary labelled cell bodies are presumably those of the preganglionic vagal neurones innervating the l.o.s. 3. In the stellate ganglia, the labelled neurones were exclusively located in the ventromedial area. It is likely that they correspond to the postganglionic adrenergic neurones of the sympathetic pathway controlling the lower oesophageal sphincter, the axons of which leave the ganglia through cardiac branches and pass in the thoracic vagus nerve to reach the sphincter (see GONELLA et al., 1979). 4. Labelled neurones were no longer observed in the medulla and in the stellate ganglia when HRP was injected in the l.o.s. after a thoracic bilateral vagotomy. 5. Labelled neurones were also observed in other thoracic ganglia from T3 to T11, most of them lying in T9 and T10. They are probably the postganglionic neurones of a second sympathetic pathway controlling the lower oesophageal sphincter, via the splanchnic nerve (see GONELLA et al., 1979). 6. A homogenous distribution of labelled neurones has been observed in the caeliac ganglia. Its functional significance is discussed.