IMMUNOELECTRON MICROSCOPIC STUDY OF PEPTIDE SUBSTANCES IN THE RAT NEUROHYPOPHYSIS / 解剖学报

ABSTRACT

The ultrastructural localization of peptide substances——VP,SP,ENK,SRIFand distribution of peptidergic nerves in rat neurohypophysis were studied by elect-ron microscopy.The results showed that VP,SP,ENK and SRIF immunoreactiveproducts located in large granular vesicles(110-150 nm in diameter),at the surfaceof microvesicles and outer membrane of mitochondria.The VP-,SP-,ENK- andSRIF-containing nerve fibers distributed at periphery of capillaries and vicinity ofpituicytes.VP- and ENK- positive nerve terminals formed axo-axonic synapses withnegative terminals.Axo-axonic synapses also existed between two SRIF-positive ter-minals.In addition,ENK- and SP-positive terminals formed synaptoid structureswith pituicytes.The authors have discovered the VP-positive pituicytes for the firsttime.The scientific significances of present paper are as follows(1)Several kinds ofpeptide such as VP,SP,ENK and SRIF have been identified in neurohypophysis atultrastructural level;(2)The discovery of VP-positive pituicytes and their peptide-rgic innervation imply that these structures probably participate in the regulation ofneurohormone releasing;(3)New morphological bases have been provided for theregulation of neurohormone releasing.