title: Histological and cytological studies on the liquor contacting peptidergic neurons in the preoptic nucleus of the Japanese eel (Anguilla japonica).
abstract: Liquor contacting peptidergic neurons (LCPNs) in the preoptic nucleus of the Japanese eel (Anguilla japonica), are investigated submacroscopically, light microscopically, electron microscopically (transmission and scanning) and histochemically. LCPNs appear in 8--13 per cent of all neurons constituting the preoptic nucleus and their cytoplasm contains many secretory granules stained by aldehyde-thionin or chrome hematoxylin. LCPNs have an epithelial cell-like polarity and their cytoplasmic organella shift to the supranuclear region. LCPNs are classified into three types (A, B, C) according to the liquor contacting portion of the cell: Granular type A neuron (40--50 x 40--50 microns 2), the cell of which is in contact with the cerebrospinal fluid (CSF), is the most common type and distributed in the ventral portion of the preoptic nucleus; this neuron is not connected with the neighboring ependymal cells by tight junctions. Bipolar type B neuron (60 x 30 micron 2), contacts the CSF with the tip of it cell process and is scattered throughout the preoptic nucleus; the cell is connected with the surrounding ependymal cells by tight junction. Bipolar type C neuron (60 x 30 micron 2) possesses a cell process protruded into the third ventricle and is distributed in the dorsal portion of the preoptic nucleus; this also is connected with the adjacent ependymal cells by tight junction. Regardless of type, all LCPNs exhibit a positive acetylcholinesterase and a negative ATPase reaction. Numerous fluorescent varicosities of monoaminergic nerve terminals are closely associated with the cell bodies of the LCPN. LCPNs are likely regulated by monoaminergic fibers.
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis; D000818:Animals; D001679:Biogenic Amines / Q000032:analysis; D002467:Cell Nucleus / Q000648:ultrastructure; D002555:Cerebrospinal Fluid; D004524:Eels / Q000033:anatomy & histology*; D005260:Female; D006651:Histocytochemistry; D008297:Male; D008855:Microscopy, Electron, Scanning; D009474:Neurons / Q000648:ultrastructure*; D010455:Peptides / Q000032:analysis* / Q000502:physiology; D011301:Preoptic Area / Q000648:ultrastructure
chemical_list: D001679:Biogenic Amines; D010455:Peptides; D000110:Acetylcholinesterase