Biosynthèse et métabolisme de l'histamine dans le système nerveux central deCarcinus maenas

Abstract

The central nervous system of Carcinus maenas synthesizes radioactive histamine when incubated in the presence of [14C] histidine and pyridoxal-5' phosphate. This biosynthesis increases linearly as a function of the amount of enzyme and the incubation time. It is not effected by heart, muscle or hepatopancreas extracts nor by haemolymph. Thus histamine appears to be synthesized mainly in the nervous system. The latter is also the seat of carcinine (beta-alanylhistamine) biosynthesis. Since carcinine seems to be a product of histamine neutralization, histamine metabolism should take place in its entirety in the nervous system. Thus histamine appears to be implicated in the neuronal activity of Carcinus. Different areas of the crustacean central nervous system: brain, eyestalks and thoracic ganglionic mass biosynthesize and metabolize histamine. Thus they all could contain sites of action for histamine. The nervous systems of two other Decapodes, Cancer and Astacus also effect histamine biosynthesis but don't metabolize it into carcinine.

Histamine operates Cl–-gated channels in crayfish neurosecretory cells

“…The presence of the histidine decarboxylase in neural structures such as thoracic ganglia, brain ganglia and eyestalks of the crab was established by measuring the conversion of [ 14 C]histidine to radioactive HA in the presence of pyridoxal-5 phosphate (Arnould, 1987). Immunohistochemical studies demonstrated the presence of HA-like reactivity in lobster stomatogastric ganglion neurons (Dando and Selverston, 1972;Sigvart and Mulloney, 1982;Mulloney and Hall, 1991), thoracic and subesophageal ganglia (Mulloney and Hall, 1991), olfactory lobe (Orona et al, 1990), median protocerebrum, and deutocerebrum and tritocerebrum (Langworthy et al, 1997).…”