当前位置： SCI文献检索 > BRAIN RESEARCH期刊下所有文献 > Quantitative immunoelectron microscopy and tannic acid study of dynamics of neurohaemal and non-synaptic peptide release by the caudodorsal cells of Lymnaea stagnalis.

Quantitative immunoelectron microscopy and tannic acid study of dynamics of neurohaemal and non-synaptic peptide release by the caudodorsal cells of Lymnaea stagnalis.

Abstract：

:The caudodorsal cells (CDCs) of the freshwater snail Lymnaea stagnalis control egg laying and egg-laying associated behaviours by releasing various peptides including the ovulation hormone CDCH. Previously it has been shown that release occurs (1) into the haemolymph from neurohaemal axon terminals in the outer compartment of the cerebral commissure, and (2) into the intercellular space of the central nervous system from non-synaptic release sites of axon collaterals in the inner compartment of the commissure. Outer and inner compartments are separated by a sheath of glial cells. In the present study the secretory dynamics of neurohaemal and collateral release have been studied. Immunoelectron microscopy with an antibody against a synthesized fragment of the egg-laying hormone [CDCH] indicates that CDCH is released by exocytosis from both sites: positive immunoreaction was found for the contents of secretory granules and contents that underwent exocytosis, and furthermore in the intercellular spaces of the inner and outer compartments. Quantitative (immunogold) electron microscopy combined with either the tannic acid-glutaraldehyde-osmium tetroxide (TAGO) method or the tannic acid-Ringer incubation (TARI) method for the visualization and quantification of exocytosis of CDCH, shows different dynamics of neurohaemal and collateral CDCH release. Neurohaemal release is strongly increased during electrical activity of the CDCs (active state). This increase does not only appear from an increased number of (immunopositive) exocytoses (3X) but also from increases in (1) the percentages of all stationary and all exocytosing granule contents that are immunopositive (both increase from 70% to 85%), (2) the degree of immunopositivity per exteriorized granule content (2X) and (3) the degree of immunopositivity in the intercellular space of the neurohaemal area (5X). Collaterals show a different picture: CDCH release particularly occurs during electrical silence (resting and inhibited states). No effect was noted of the electrical state of the CDCs on the percentages of CDCH-immunoreactive stationary or exteriorized granule contents, nor on the degree of immunopositivity of the exteriorized contents. Furthermore, the degree of immunopositivity in the intercellular space of the inner compartment is drastically decreased (8X). Finally, both in the resting and the active state, the percentage of CDCH-positive exocytosing contents in the collaterals is smaller than that of CDCH-positive stationary contents whereas in the neurohaemal area these percentages do not differ.(ABSTRACT TRUNCATED AT 400 WORDS)

journal_name

Brain Res

journal_title

Brain research

authors

Schmidt ED,Roubos EW

doi

10.1016/0006-8993(89)90866-4

subject

Has Abstract

pub_date

1989-06-12 00:00:00

pages

325-37

issue

eissn

0006-8993

issn

1872-6240

pii

0006-8993(89)90866-4

journal_volume

489

pub_type

杂志文章

在线工具

Quantitative immunoelectron microscopy and tannic acid study of dynamics of neurohaemal and non-synaptic peptide release by the caudodorsal cells of Lymnaea stagnalis.