Table Of ContentAdvances in Anatomy, Embryology and Cell Biology
Ergebnisse der Anatomie und Entwicklungsgeschichte
Revues d'anatomie et de morphologie experimentale
50/2
Editors
A. Brodal, Oslo· W. Hild, Galveston' J. van Limborgh, Amsterdam
R. Ortmann, Koln . T.H. Schiebler, Wurzburg. G. Tondury, Zurich· E. Wolff, Paris
I. Vigh-Teichmann, B. Vigh
The Infundibular Cerebrospinal-Fluid
Contacting Neurons
With 24 Figures
Springer-Verlag Berlin Heidelberg New York 1974
Dr. Ingeborg Vigh-Teichmann and Dr. Bela Vigh
2nd Department of Anatomy, Histology and Embryology
Semmelweis University Medical School, Budapest
Tiizolt6 utca 58, Budapest 1094jHungary
lSBN-13: 978-3-540-06979-9 e-lSBN-13: 978-3-642-95266-1
DOl: 10.1007/978-3-642-95266-1
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to the publisher, the amount of the fee to be determined by agreement with the publisher. © by Springer· Verlag
Berlin·Heidelberg 1974.
Library of Congress Cataloging in Publication Data. Vigh·Teichmann, 1932-. The infundibular cerebrospinal·
fluid'contacting neurons. (Advances in anatomy, embryology, and cell biology; v.50, fase. 2). Includes biblio·
graphical references and index. 1. Cerebrospinal fluid. 2. Infundibulum (Brain). I. Vigh, Bela, joint author.
II. Title. III. Series. [DNLM: 1. Cerebrospinal fluid. 2. Hypothalamus·Cytology. 3. Neurons·Cytology. 4. Neuro
secretory systems-Cytology. W1AD433K v.50 fasc.2 I WL312 V675i]. QL801.E67. vol. 50, fasc.2. [QP375].
574.4'08s. [596'.01'88] 74·23326.
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Contents
InJroduction . . 7
H i8t0rical Review 8
Material and Method8 10
11
A. The Infundibular CSF Contacting Neurons of Fishes 11
I. The CSF Contacting Neurons of the Periventricular Hypothalamic Nucleus. 11
Light Microscopy 11, Electron Microscopy 13, Discussion 16
II. The CSF Contacting Neurons of the Nucleus Lateralis Tuberis . . . . .. 19
Light Microscopy 20, ffitrastructure 22, Discussion 24
III. The CSF Contacting Neurons of the Vascular Sac . . . . . . . 27
Light Microscopy 28, Electron Microscopy 28, Discussion 30
B. The CSF Contacting Neurons of the Infundibular Lobe of Amphibians 32
Light Microscopy 33, Electron Microscopy 35, Discussion 37
C. The CSF Contacting Neurons of the Infundibular Nucleus of Amniote Vertebrates 40
1. Comparative Light Microscopy. . . . . . . . . . . . . . . . . . . . . . . 41
Histology 41, AChE reaction 46
2. Comparative Ultrastructure . . . 47
Reptiles 47, Birds 53, Mammals 55
3. Discussion. . 60
General ConclUllions 68
Summary. 74
References 76
Subject Index . 89
Introduction
The infundibular region forms an important part of the hypothalamic peri
ventricular grey substance. By morpho-physiological examinations its nuclei were
affirmed to be generally significant as high-leveled centres for the regulation of
various vegetative functions: heart frequency, blood pressure, intestine motility,
feeling of hunger, satiety and thirst, and homeostasis of temperature. Moreover,
emotional and sexual reactions as well as the regulation of behaviour depend on
the hypothalamic nuclei. Most frequently, researchers dealt with the role of the
neurosecretory supraoptic, paraventricular and infundibular nuclei for water and
salt household and for the control of endocrine glands.
Furthermore, the hypothalamus, especially its ventricular wall was suggested
by a series of physiological studies to have different receptory functions like
osmoreception, glucose reception, thermoreception etc. (Verney, 1947; Hellon,
1972; Andersson, 1972, a.o.). However, the morphological investigation of the
corresponding receptor structures remained far behind for a considerable time.
Our present contribution demonstrating a special hypothalamic neuron type seems
to be closely connected exactly with this morphological problem.
Our own studies started with the comparative morphological investigation of
the magnocellular neurosecretory system and its neurons extending one of their
processes into the cerebrospinal fluid (CSF). We found that they form intravent
ricular dendrite terminals resembling well known receptor endings (Vigh-Teich
mann, 1969, Vigh-Teichmann, Vigh and Aros, 1970b). Further, it was shown by
us that these so-called CSF contacting neurons ("Liquorkontaktneurone", Vigh,
Teichmann and Aros, 1969) are present not only in the classic neurosecretory
nuclei but also in the infundibular cell groups (Vigh-Teichmann, Vigh and Aros,
1970a, 1971 b, etc.) and in other hypothalamic and even spinal areas. These CSF
contacting neurons, further intraventricular axons (see later) represent the so
called CSF contacting neuronal system (lit. in Vigh and Vigh-Teichmann, 1973).
The CSF contacting cells supplied with receptor-like intraventricular terminals
may be responsible for the physiologically demonstrated, and for eventually still
unknown receptory functions of the hypothalamus.
The CSF contacting neurons appear in an unexpected large number in the wall
of the 3rd ventricle. Especially in lower vertebrates, almost every periventricular
nucleus of the hypothalamus contains and/or consists of such cells. On the other
hand, apart from the area around the central canal of the spinal cord and medulla
oblongata, the hypothalamic periventricular grey is the only place where CSF
contacting neurons occur. As they are dominating elements in the organization
of the hypothalamus they must dominate also in its function. In this respect,
the investigation of the CSF contacting neurons may open new perspectives to
clarify the role of the hypothalamus.
The network of the CSF contacting neurons is more developed in lower than
in higher vertebrates. Nevertheless, it is also present in the infundibular region of
8 I. Vigh-Teichmann and B. Vigh
mammals, a fact indicating the infundibular nuclei to be more closely connected
with the CSF than the other neuron groups of the hypothalamus.
It is worthy to note that the detection of the CSF contacting neuronal
structures of mammals was only possible on the basis of comparative morphological
studies of the more evident CSF contacting neuronal system in lower vertebrates.
For the last years, the infundibular region itself has been in the limelight of a
considerable number of physiological contributions proving the significance of the
infundibular nuclei and adjacent structures for the humoral regulation of the
secretory activity of adenohypophysial gland cells. The CSF contacting neurons
in these hypothalamic nuclei-as demonstrated by us-may be important by
influencing in some way or other, the regulation of the neuroendocrine system.
When surveying literature, it appears that data on the morphology of the
infundibular region are relatively rare compared with the number of physiological,
biochemical and pharmacological studies. It seems, therefore, justified to sum
marize our morphological results concerning the comparative anatomy, light and
electron microscopy and enzymehistochemical studies on the infundibular nuclei
and their CSF contacting neurons in different vertebrate classes.
Morphologically, the infundibular periventricular grey includes different nerve
cell groups in different classes of vertebrates: in fishes the periventricular hypo
thalamic nucleus, nucleus lateralis tuberis and the nerve cells of the vascular sac,
in amphibians the neurons of the infundibular lobe, in reptiles and birds the
infundibular nuclei, and in mammals the arcuate sive infundibular nuclei. All
these areas contain CSF contacting nerve cells.
In our present contribution we have divided the results into three main chap
ters A, B, C. In the first, we deal with our findings in fishes, in the second
those in amphibians and in the third those in amniote vertebrates, i.e. reptiles,
birds and mammals.
We hope our comparative morphological review will provide a basis for the
evaluation and control of experimental morpho-physiological observations of the
infundibular region of the hypothalamus.
Historical Review
From the beginning of our century on, several authors reported upon intra
ependymal cells in the brain an spinal cord that form intraventricular protrusions
detectable by silver impregnations (Tretjakoff, 1909, 1913; Franz, 1912; Kolmer,
1921; Agduhr, 1922). Later, these investigations became scarce. They remained
unnoticed and unconfirmed up to the era when the use of electron microscopy
gave new stimuli for ultrastructural as well as conventional light microscopic
research in the ventricular wall.
Our former investigations on the paraventricular organ lead us to detect
similar cells and to recognize and extended system of them called CSF contacting
neuronal system. Up to that time, the paraventricular organ, one of the ependymal
organs of the 3rd ventricle appeared in the literature as an exclusively ependymal
territory analogous with the subcommissural organ (lit. in Vigh, 1971; Vigh and
Vigh-Teichmann, 1973). When studying the so-called secretory coagUlum on the
Infundibular CSF Contacting Neurons 9
ventricular surface of the paraventricular organ Takeichi (1965, 1967) reported
upon nerve endings of unknown origin. Almost contemporarily, Vigh and Teich
mann (1966), Vigh, Teichmann and Aros (1967) likewise demonstrated these nerve
endings a.nd furthermore the corresponding perikarya. We established that in
addition to an ependymal part there exists a neuronal component, too, in the
organ. This neuron group was named "nucleus organi paraventricularis"(Vigh
and Teichmann, 1966; Vigh, Teichmann and Aros, 1967, Vigh, 1971).
It could be proven unequivocally by light and electron microscopy that one
of the processes of the bipolar and multipolar neurons of the paraventricular
organ protrudes across the ependyma into the lumen of the 3rd ventricle and
forms a free, knob-like terminal there (Vigh and Teichmann, 1966; R6hlich and
Vigh, 1967; Vigh, Tar and Teichmann, 1968; Vigh and Majorossy, 1968). These
results were confirmed. also by other authors (Braak, 1967, 1968, 1970; Braak
and von Hehn, 1969; Peute, 1969, 1971, 1974).
Our electron microscopic investigations revealed that the intraventricular
nerve endings of the paraventricular organ were dendritic in nature. They
were provided with an atypical cilium supplied with basal bodies and rootlet fibers.
As the structure of the bipolar cells and their dendrite terminals in the CSF
resembled that of already known receptor cells (Vinnikov, 1969) Vigh (1967,
1968, 1969, 1970, 1971) attributed mainly a receptory function to the neurons
of the organ.
Thereafter, we reinvestigated the nerve cells described by Kolmer (1921) and
Agduhr (1922) around the central canal of the spinal cord. It was an exciting
electron microscopic and histochemical finding for us that these neurons resembled
in their principal morphology those of the paraventricular organ (Vigh-Teichmann
and Vigh, 1969a, 1970; Vigh, Vigh-Teichmann and Aros, 1970, 1971a, b, 1974;
Vigh, Vigh-Teichmann, Koritsansky and Aros, 1970, 1971; Vighand Vigh-Teich
mann, 1971, 1973). This proved that the intraependymal nerve cells of the spinal
cord belong to the same system as the CSF contacting neurons of the para
ventricular organ.
It was also known for a long time that processes of the magnocellular neuro
secretory nuclei pass to the 3rd ventricle (lit. in Vigh-Teichmann, Vigh and Aros,
1970b; Vigh, 1971; Vigh and Vigh-Teichmann, 1973). The association of our find
ings on the special neurons of the paraventricular organ with the data of the
earlier authors induced us to investigate the classic neurosecretory nuclei <1f the
hypothalamus. We found that their ventricular processes form likewise intra
ventricular dendrite endings being ultrastructurally completely analogous with
those of the paraventricular organ (Vigh-Teichmann, 1969, 1971 ; Vigh-Teichmann,
and Vigh, 1969a, b, 1970; Vigh-Teichmann, Vigh and Aros, 1970a, b; Vigh
Teichmann, Vigh and Koritsansky, 1970a). In addition, neurons exhibiting similar
characteristics were detected also in the parvocellular preoptic area (Teichmann
and Vigh, 1968; Vigh-Teichmann, 1969, 1971; Vigh-Teichmann, R6hlich and
Vigh, 1969; Vigh-Teichmann, Vigh and Aros, 1969b, 1970a, 1971a; Vigh-Teich
mann and Vigh, 1969a, b).
Our morphological results on the magnocellular neurosecretory nuclei speak in
favour of a receptory function of their CSF contacting terminals in contrast
to the hypothesis of the earlier authors who suggested the ventricular processes
10 1. Vigh-Teichmann and B. Vigh
of the neurosecretory cells to be secretory elements discharging their neuro
secretory granules by macro-apocrine secretion into the ventricle (lit. in Scharrer
and Scharrer, 1954; Diepen, 1962).
As we found CSF contacting neurons in the magnocellular Gomori-positive
neurosecretory nuclei we supposed that even the parvocellular neurosecretory
system might contain such cells. Therefore, we extended our studies to its neuron
groups including the whole infundibular region of different vertebrates. The finding
that here, too, nerve cells occur forming intraventricular terminals in the CSF,
fitted well into our concept (Vigh-Teichmann, Vigh and Aros, 1970a, 1971 b,
1973; Vigh-Teichmann, Vigh, Koritsansky and Aros, 1970; Vigh-Teichmann, 1971 ;
Vigh and Vigh-Teichmann, 1973; Vigh-Teichmann and Vigh, 1974). Finally, in
the course of enzymehistochemical investigations we observed large intraventri
cular dendrite terminals in the nucleus lateralis tuberis of fishes (Vigh-Teichmann,
Vigh and Koritsanszky, 1970b; Vigh, 1971; Vigh and Vigh-Teichmann, 1973).
These were the main stations of the description of the CSF contacting neurons.
These results obtained in different hypothalamic nuclei and the comparative
morphological data in different vertebrates profoundly influenced our conception
on the structural organization and functional aspects of the hypothalamus, first
of all of the infundibular region.
Material and Methods
The hypothalamus of a total of 660 animals was studied by light and electron
microscopy.
Light Microscopy. 607 brains of the following species were investigated:
Fishes: 28 Cyprinus carpio, 15 anguilla (vulgaris), 15 Amiurus nebulosus, 27 Carassius
auratus, 8 Ctenopharyngodon idella;
Amphibians: 32 Amblystoma mexicanum, 26 Triturus vulgaris, 25 Triturus cristatus,
25 Pleurodeles waltlii, 63 Rana esculenta;
Reptiles: 30 Emys orbicularis, 3 Testudo hermanni, 15 Pseudemys scripta elegans,
7 Natrix natrix, 17 Lacerta viridis, 27 Lacerta agilis, 7 Anguis tragilis;
Birds: 10 Passer domesticus, 10 Turdus merula, 5 Columba livia, 5 Streptopelia decaocto,
5 Gallus domesticus, five 1-year-old hen and cock, 30 chicken embryos (white leghorn) of stage
32,36,38,42 and 45 according to Hamburger and Hamilton (1951), 30 4-day-old, 6-day-old
and 4-week-old chickens;
Mammals: 109 Epimys norvegicus, 12 Felis domestica, 15 Cavia cobaya, 5 Oryctolagus
cuniculus and 5 Erinaceus roumanicus.
The brains were fixed in Bouin's fixative, formol-glacial acid-alcohol mixture or in cold
4% neutral formol containing 1 % CaCl and 0.22 M beet-sugar (1 to 2 hrs at 4°C). The
2
Bouin-fixed hypthalami were dehydrated, embedded in paraffin, sectioned 5 fL thick and stained
with chrome alum hematoxylin phloxin (Bargmann, 1949), aldehyde fuchsine (Gabe, 1953),
chrome alum galiocyanin (Bock, 1966) and hematoxylin eosin. Bodian's impregnation
technique was performed on paraffin sections (15 fL thick) of the brains fixed in alcohol
containing mixture.
The Ca-formol-fixed material was rinsed in cold 0.22 M sucrose solution for 30 min, and in
gum-sucrose solution for 18 hrs at 4°C (see in Pearse, 1968, 1972). Serial sections of
10 fL thickness were cut in a cryostat, mounted on albumonized slides and used for the
histochemical demonstration of acetylcholinesterase (AChE) according to Karnovsky and Roots
(1964). Substrate: acetylthiocholine iodide, incubation time: 60 to 90 min at 4°C, pH 6.0.
Butyrylcholinesterase was inhibited by adding iso-OMPA (tetraisopropylpyrophosphoramide)
to the incubation medium in a final concentration of 10-5 M. Moreover, some brains
(Carassius auratus, Emys orbicularis) were used for the demonstration of monoamine oxidase
Infundibular CSF Contacting Neurons 11
(MAO) according to Urano (1972). Mao activity was completely inhibited by 10-3 M Marsilid
( 1-isonicotin-2-iso-propylhydrazin phosphate).
Furthermore, semithin sections of the electron microscopic material were stained with
toluidine blue azure II.
Electron microscopy. A total of 52 animals was investigated: Cyprinus carpio, Anguilla
vulgaris, Triturus eristatus, Bulo bulo, Bombinator igneus, Rana eseulenta, Emys orbicularis,
Lacerta viridis, Lacerta agilis, Lacerta muralis, Gallus domesticus, Cavia eobaya (4-day-old,
2-week-old, 2-month-old), Epimys norvegieus, Erinaeeu8 roumanieu8, Felis domestica,
Oryctolagus euniculus. Blood was washed off by perfusion with dextran solved in 0.9% NaCl,
for 20 sec. Fixation by aortio perfusion with 5% or 6% glutaraldehyde solved in 0.1 M
oacodylate buffer or Millonig phosphate buffer of pH 7.2 for 15 min. Brains were quiokly
removed from the skull, the postohiasmatio part of the hypothalamus exoised, and fixated
on up to 2 hrs. Quick washing in cold buffer, postfixation in 1 % OsO, solved in buffer,
for 2 hrs at 4°C. Dehydration in ethanol, embedding in araldite. Ultrathin sections out on a
Reiohert OMU -2 ultramicrotome were stained with uranylaoetate and lead oitrate, and examined
in a JEM 6C eleotron miorosoope.
Results
As already mentioned 'in the introductory part of our contribution the results
were divided into three main chapters dealing with the infundibular OSF
contacting neurons of fishes (A), amphibians (B) and amniote vertebrates (0).
A. The Infundibular CSF Contacting Neurons of Fishes
In this chapter we summarize the data available on the OSF contacting
nerve cells of the infundibular region of fishes. The following areas are dealt with:
the periventricular hypothalamic nucleus (I), the nucleus lateralis tuberis (II)
and the vascular sac (III).
I. The CSF Contacting Neurons of the Periventricular
Hypothalamic Nucleus
The region of the periventricular grey matter named nucleus periventricularis
hypothalami is situated behind the optic chiasm and transversal commissure,
caudally and ventrally from the magnocellular preoptic nucleus, and extends up
to the nucleus lateralis tuberis.
In the literature, there are no data about the morphology and function of t~ts
region and about its relation to the 3rd ventricle. Therefore, we have investigated
the periventricular hypothalamic nucleus by light and electron microscopy in
Oyprinus carpio, Oarassius auratus, Amiurus nebulosus, Otenopharyngodon idella
and Anguilla vulgaris (Vigh-Teichmann and Vigh, 1969a, Vigh-Teichmann, Vigh
and Aros, 1970a; Vigh-Teichmann, Vigh and Koritsansky, 1970b; Vigh, 1971;
Vigh and Vigh-Teichmann, 1973).
Light Microscopy
In Oyprinus carpio, the region of the periventricular hypothalamic nucleus
consists of a magnocellular part situated in dorso-anterior position, and of a
parvocellular part arranged ventro-posteriorly. It should be mentioned that the
nerve cells of the dorsal compartment of the nucleus are much smaller than the
12 1. Vigh-Teichmann and R Vigh
.
. .. .. ..
. .
• . '
v
Fig. 1 a-e. Details of the periventricular hypothalamic nucleus of Cyprinu8 carpio. (a) Strong
AChE activity in the magnocellular part of the nucleus (M). V 3rd ventricle. X 160.
(b) AChE-positive hypendymal nerve cells. At narrow CSF contacting dendrite terminal.
E AChE-negative ependyma. X 280. (c) CSF contacting neurons (plasmalemma dotted) with
dark and light nuclei. Toluidine blue azur II. X 1120. (d) CSF contacting dendrite terminal
(DT). A intraventricular axon forming axo-dendritic synapse (at arrow), B basal body,
C cilium, D desmosome-like junctions, E ependyma, R rootlet fiber, V 3rd ventricle.
X 32400. (e) Perikaryon of CSF contacting neuron. G dense-core vesicles, N nucleus. X 8320
