Hypothalamic angiotensinergic fibre systems terminate in the neurohypophysis

doi:10.1016/0304-3940(89)90240-1

Neuroscience Letters

Volume 96, Issue 1, 2 January 1989, Pages 42-46

https://doi.org/10.1016/0304-3940(89)90240-1 Get rights and content

Abstract

A new affinity-purified anti-angiotensin $II III$ antibody (‘BODE’) was used to determine the location of angiotensin-like immunoreactivity in the paraventriculo-hypophysical pathway, especially in the pituitary. Angiotensin-like immunoreactivity was shown to be concentrated in the neurohypophysis and was characterised by a dense plexus of fibres and terminals.

References (14)

T. Akaishi et al.
Responses of paraventricular and supraoptic units to angiotensin II, Sar¹-Ile⁸-angiotensin II and hypertonic NaCl administered into the cerebral ventricle
Brain Res.
(1980)
K. Fuxe et al.
Immunohistochemical evidence for the existence of angiotensin II-containing nerve terminals in the brain and spinal cord of the rat
Neurosci. Lett.
(1976)
R.L. Hauger et al.
Characterization of angiotensin II receptors in the anterior pituitary gland
Mol. Cell. Endocrinol.
(1982)
H. Imboden et al.
Improved immunohistochemical staining of angiotensin II in rat brain using affinity purified antibodies
Brain Res.
(1987)
A.N. Epstein
Hormonal synergy as the cause of salt appetite
C.M. Ferrario
Neurogenic actions of angiotensin II
Hypertension
(1983)
J.T. Fitzsimons
Thirst
Physiol. Rev.
(1972)

There are more references available in the full text version of this article.

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Citation Excerpt :
There are also dichotomies concerning the localization of the peptide, Ang II, and its receptors. For example, there is dense staining for Ang peptides in PVN, SON, median eminence and the neurohypophyseal tracts, while the receptors are concentrated in the SFO, anterior ventricular region and PVN [15,16,20,34]. Molecular genetic studies provided the first evidence that AT1 receptors exist in two different forms [4,23].
Experiments were performed to study angiotensin (Ang) AT1a and AT1b mRNA expression in mice, including, examination of brain distribution and the effect of salt loading. In situ hybridization (ISH) methods showed that the pattern of mRNA expression was identical for AT1a and AT1b, with cellular labeling in rostral forebrain, hypothalamus and brainstem. Receptor mRNAs were concentrated in brain regions involved in the regulation of electrolyte and cardiovascular balance. Immunocytochemistry with AT1 specific antisera showed a pattern that was consistent with the ISH. Reverse transcriptase-polymerase chain reaction (RT-PCR) of hypothalamus and pituitary verified the presence of both AT1a and AT1b mRNA. Using quantitative ISH, we found that AT1a mRNA expression was significantly increased after 5 days of 2% NaCl consumption in anterior third ventricle (AV3V), paraventricular hypothalamus (PVN) and subfornical organ (SFO), but unchanged in anterior pituitary. There were no significant changes in AT1b mRNA. These results document the utility of ISH coupled with quantitative imaging techniques for the study of subtype specific expression. Using ISH and RT-PCR, we verified that AT1a and AT1b receptors are expressed in mouse brain and pituitary and show a similar pattern of distribution. Salt loading produced a specific increase in AT1a mRNA in osmosensitive regions, suggesting that this receptor subtype is regulated by sodium/osmolar input.
Immunocytochemical localization of angiotensin II receptor subtypes and angiotensin II with monoclonal antibodies in the rat adrenal gland
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Angiotensin II (Ang II), a major regulator of cardiovascular function and body fluid homeostasis, mediates its biological actions via two subtypes of G protein-coupled receptors, termed AT₁ and AT₂. The primary goal of this study was to raise monoclonal anti-peptide antibodies specific to angiotensin AT₁- and AT₂-receptor subtypes and to Ang II itself and using these monoclonal antibodies to determine the intraadrenal localization of AT₁ and AT₂ receptors and Ang II in male adult rats. Immunocytochemistry unambiguously demonstrates a regional colocalization of Ang II and angiotensin II receptors in the adrenal gland. The novel antibodies localized Ang II and the AT₁ receptors to the zona glomerulosa of the cortex and to the medulla whereas AT₂ receptors were limited to the medulla. The specificity of immunostaining was documented by pre-adsorption of the antibody with the immunogenic peptide. Our data underscore that AT₁ appears to mediate most of the physiological actions of Ang II in adrenal. Western blot analysis of rat adrenal protein extracts using AT₁ antibody showed a predominant 73-kDa band and a weaker 97-kDa immunoreactive band corresponding to glycosylated forms of the AT₁ receptor. Immunostaining with anti-AT₂ yielded one major immunoreactive band of 73-kDa size and one additional fainter band of 120 kDa. These antibodies may prove of value in unraveling the subcellular localization and intracellular effector pathways of AT₁ and AT₂.
A new angiotensinergic system in the CNS of the rat
2001, Regulatory Peptides
The use of two different polyclonal, affinity-purified, monospecific antibodies to ANG II (called BODE and BODE 1) revealed dissimilar distribution of ANG II immunoreactivity within the rat central nervous system (CNS). The ANG II-like material detected using BODE was concentrated in the neurosecretory hypothalamic nuclei, in the inner layer of the median eminence and in the posterior lobe of the pituitary. In contrast, the BODE 1 antibody did not stain the hypothalamic–neurohypophysial angiotensinergic system, and the staining pattern was much more broadly distributed throughout the CNS. BODE 1 is the first antibody that can be used to verify the locations of endogenous angiotensin and their receptor sites in the CNS. The diverse distribution of the ANG II-like material detected by the two antibodies provides strong evidence for the existence of at least two different angiotensinergic systems in the CNS.
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2000, Journal of Neuroscience Methods
This study was carried out to characterize angiotensin II (ANG II) sensitive neurons in the hypothalamic paraventricular nucleus (PVN) of the rat. An approach was chosen in which a combination of an electrophysiological, a morphological, and an immunocytochemical method was focused on one single neuron. The cell’s reaction to an application of ANG II and its specific antagonist Losartan (Dup753) was investigated using the technique of intracellular recording inside 450-μm-thick brain slices. A final injection of a fluorescent dye labelled the neurons. Optical sections were taken through the marked cells by a confocal laser-scanning microscope and made into a three-dimensional cell model on a computer. One-micrometer thin sections were cut from the thick slice at the level of the electrophysiologically characterized and marked cell body for immunocytochemical tests with different antibodies. Our results show an example of such a neuron inside the PVN excited by ANG II. It was possible to block this excitation with the specific ANG II receptor subtype 1 (AT₁) antagonist Losartan. The result indicated that the ANG II reaction was mediated by the AT₁ receptor subtype. Immunocytochemical studies show that this ANG II-sensitive neuron contains ANG II but no vasopressin. The combination of the results enables us to gain improved information on interactions of peptidergic systems.
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The existence and colocalization of angiotensin II- and vasopressin-like immunoreactivity in individual magnocellular cell groups of the hypothalamus has been demonstrated by using immunocytochemical methods. These neurosecretory magnocellular groups consist of the paraventricular nucleus and the supraoptic nucleus, as well as different accessory cell groups. The fibers from the neurons of the accessory nuclei project directly to adjacent blood vessels and do not comigrate with the hypothalamo–neurohypophysial fiber pathway. On the basis of these findings it can be concluded that in the hypothalamus two different angiotensinergic and vasopressinergic neurosecretory systems exist: (1) an intrinsic hypothalamic and (2) a hypothalamo–neurohypophysial system. The distribution of the accessory cell groups in the hypothalamus is shown in a 3D reconstruction which includes the connection of these magnocellular nuclei with the vascular system in this area.

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Hypothalamic angiotensinergic fibre systems terminate in the neurohypophysis

Abstract

Brain Res.

Neurosci. Lett.

Mol. Cell. Endocrinol.

Brain Res.

Hormonal synergy as the cause of salt appetite

Neurogenic actions of angiotensin II

Hypertension

Thirst

Physiol. Rev.