CYTOLOGICAL AND IMMUNOCYTOCHEMICAL STUDY OF THE SINUS GLAND IN THE NORWAY LOBSTER NEPHROPS-NORVEGICUS (L.)

Light and transmission electron microscopic examination of the X-organ -sinus gland complex in adult Nephrops norvegicus reveals a high densi ty of active neurosecretory axon endings (53%) abutting onto an undula tory-release surface. At least six different categories of neurosecret ory granules and related vesicles have been identified on the basis of their texture, electron density, and diameter. Computer-aided three-d imensional reconstruction of N. norvegicus sinus gland defined by its fuchsinophilia on 2.5 mu m serial sections shows a multilobed organ 1. 25x 10(-2) mm(3) in volume. Immunocytochemical studies were carried ou t using polyclonal antibodies raised against purified Astacus leptodac tylus CHH (Gorgels-Kallen and Van Herp, 1981) and Homarus americanus G IH (Meusy and Soyez, 1991). Immunocytochemical localization of CHH and GIH (VIH) at the LM and EM level specifically locate the massive pres ence of CHH and a more superficial and scattered distribution of GIH i n the axon endings. Under TEM, specificity in type and content of gran ules appears to be confined to single axons. Heterologous antibodies r eacting with even phylogenetically distant taxa stress a conservative homology at least of some common reactive epitopes.