Localisation of monoamines in nerves of the posterior salivary gland and salivary centre in the brain of Octopus

Summary Slices of the posterior salivary gland and of the superior buccal lobe of the brain of Octopus vulgaris take up ³H-5-hydroxytryptamine in vitro. By light and electron microscopical radioautography the uptake is localised in certain neuronal perikarya and axonal varicosities in the superior buccal lobe, and in nerves that end in the secretory tubules of the posterior salivary gland. These structures do not incorporate ³H-noradrenaline. After formaldehyde histochemistry, monoamine fluorescence is found in some neuronal perikarya of the superior buccal lobe, and in nerves entering the secretory tubules of the gland. The posterior salivary gland nerve, which originates in the superior buccal lobe and supplies the gland, shows a pronounced accumulation of fluorescence on the proximal side of a ligature applied in vivo. It is suggested that monoamines are transported from the brain to the gland by the posterior salivary gland nerves.J. B. would like to thank the Science Research Council, Great Britain, for financial support.