Résumé
Ablation/ligation, injection and gill perfusion experiments of different neuroendocrine centers such as the X-organ/sinus gland complex (XO/ SG) in the eyestalk, central nervous system, thoracic ganglia and the pericardial organs have demonstrated a neuroendocrine control of hydro-mineral homeostasis in crustaceans. The thoracic ganglia and pericardial organs contain mainly biogenic amines that have respectively effects on water movements and Na+ uptake via the activation of Na+/K+-ATPase with cAMP as second messenger. The eyestalk XO/SG complex synthesizes and stores a family of neuropeptides among which the Crustacean Hyperglycemic Hormone (CHH) appears as an important neuroendocrine factor influencing osmo- and iono-regulatory mechanisms. Recent investigations have revealed different CHH isoforms in crustaceans. In Astacidae, two CHH enantiomers are present, a levogyre (L-CHH) and a dextrogyre (D-Phe3-CHH) form, but only the D-isomer has a stimulating effect on osmoregulatory parameters. In Brachyura, different CHH-related peptides are stored in and released from different endocrine organs and they seem to act on ion homeostasis and water balance in several target organs depending on environmental or physiological stimuli.