Molt-inhibiting hormone immunoreactive neurons in the eyestalk neuroendocrine system of the blue crab, Callinectes sapidus

The production of ecdysteroid molting hormones by crustacean Y-organs is ne gatively regulated by a neuropeptide, molt-inhibiting hormone. It is genera lly agreed that molt-inhibiting hormone is produced and released by the eye stalk neuroendocrine system. In the present study, immunocytochemical metho ds were used to detect molt-inhibiting hormone immunoreactive neurons in ey estalk ganglia of the blue crab, Callinectes sapidus. The primary antiserum used was generated against molt-inhibiting hormone of the green shore crab , Carcinus maenas. A preliminary Western blot analysis indicated the antise rum binds molt-inhibiting hormone of Callinectes sapidus. Using confocal an d conventional immuno fluorescence microscopy, molt-inhibiting hormone immu noreactivity was visualized in whole mounts and thin sections of Callinecte s sapidus eyestalk ganglia. Immunoreactivity was detected in 15-25 neurosec retory cell bodies in the medulla terminalis X-organ, their associated axon s and collateral branches, and their axon terminals in the neurohemal sinus gland. The cellular organization of molt-inhibiting hormone immunoreactive neurons in blue crabs is generally similar to that reported for other crab species. The combined results suggest the cellular structure of the molt-i nhibiting hormone neuroendocrine system is highly conserved among brachyura ns. (C) 2001 Elsevier Science Ltd. All rights reserved.