Antidipsogenic actions of endothelins are exerted via the endothelin-A receptor in the brain

1993 ◽  
Vol 265 (5) ◽  
pp. R1212-R1215 ◽  
Author(s):  
W. K. Samson ◽  
T. C. Murphy

The receptor subtype mediating the antidipsogenic effects of the endothelins (ETs) was determined in conscious, unrestrained, normally hydrated rats. Intracerebroventricular injection of 6, 12, and 20 ng ET-2 resulted in a significant, dose-related inhibition of water drinking in response to subsequent injection of 100 pmol angiotensin II (ANG II). Pretreatment with 50 or 100 ng ET-B receptor agonist failed to alter the subsequent drinking response to ANG II. Drinking in response to ANG II was significantly accentuated in rats pretreated with 50, 100, and 200 ng of the selective ET-A receptor antagonist BQ-123. These data indicate that the antidipsogenic effects of the ETs are mediated via the ET-A receptor subtype and further suggest that endogenous ET plays a physiologically relevant role in the central nervous system control of fluid and electrolyte homeostasis.

2018 ◽  
Vol 25 (28) ◽  
pp. 3333-3352 ◽  
Author(s):  
Natalia Pessoa Rocha ◽  
Ana Cristina Simoes e Silva ◽  
Thiago Ruiz Rodrigues Prestes ◽  
Victor Feracin ◽  
Caroline Amaral Machado ◽  
...  

Background: The Renin-Angiotensin System (RAS) is a key regulator of cardiovascular and renal homeostasis, but also plays important roles in mediating physiological functions in the central nervous system (CNS). The effects of the RAS were classically described as mediated by angiotensin (Ang) II via angiotensin type 1 (AT1) receptors. However, another arm of the RAS formed by the angiotensin converting enzyme 2 (ACE2), Ang-(1-7) and the Mas receptor has been a matter of investigation due to its important physiological roles, usually counterbalancing the classical effects exerted by Ang II. Objective: We aim to provide an overview of effects elicited by the RAS, especially Ang-(1-7), in the brain. We also aim to discuss the therapeutic potential for neuropsychiatric disorders for the modulation of RAS. Method: We carried out an extensive literature search in PubMed central. Results: Within the brain, Ang-(1-7) contributes to the regulation of blood pressure by acting at regions that control cardiovascular functions. In contrast with Ang II, Ang-(1-7) improves baroreflex sensitivity and plays an inhibitory role in hypothalamic noradrenergic neurotransmission. Ang-(1-7) not only exerts effects related to blood pressure regulation, but also acts as a neuroprotective component of the RAS, for instance, by reducing cerebral infarct size, inflammation, oxidative stress and neuronal apoptosis. Conclusion: Pre-clinical evidence supports a relevant role for ACE2/Ang-(1-7)/Mas receptor axis in several neuropsychiatric conditions, including stress-related and mood disorders, cerebrovascular ischemic and hemorrhagic lesions and neurodegenerative diseases. However, very few data are available regarding the ACE2/Ang-(1-7)/Mas receptor axis in human CNS.


1994 ◽  
Vol 267 (3) ◽  
pp. R786-R791 ◽  
Author(s):  
A. Moriguchi ◽  
C. M. Ferrario ◽  
K. B. Brosnihan ◽  
D. Ganten ◽  
M. Morris

The transgenic (TG) rat carrying the mouse renin gene (mRen-2d) has provided a unique opportunity to explore central interactions between the brain renin-angiotensin (RAS) and vasopressin (AVP) systems. To evaluate the hypothalamic vasopressin axis in the TG rat, we measured the central nervous system concentrations of AVP and determined the effect of angiotensin II (ANG II) and its NH2-terminal heptapeptide [angiotensin-(1-7)] on blood pressure, heart rate, and AVP release using brain microdialysis. Intracerebroventricular infusion of ANG II or ANG-(1-7) in control rats increased local AVP release from the paraventricular and supraoptic nuclei. The ANG II infusion was associated with a significant increase in blood pressure not observed with ANG-(1-7). In contrast, the angiotensin peptide-induced central AVP responses and the ANG II-induced blood pressure increase were absent in the TG animal. The plasma AVP responses to ANG II and ANG-(1-7) were comparable in the control and TG rats. The TG rats exhibited a 22-fold higher level of AVP in the dorsal lower brain stem but had lower AVP levels in the posterior pituitary and the median eminence compared with control rats. These results suggest that insertion of the mouse renin gene into the rat genome leads to alterations in the AVP axis in terms of AVP peptide content and angiotensin-induced cardiovascular and AVP responses.


SIMULATION ◽  
2003 ◽  
Vol 79 (11) ◽  
pp. 648-669 ◽  
Author(s):  
Angela Nebot ◽  
Francisco Mugica ◽  
François E. Cellier ◽  
Montserrat Vallverdú

2002 ◽  
Vol 282 (3) ◽  
pp. R865-R869 ◽  
Author(s):  
Chagriya Kitiyakara ◽  
William J. Welch ◽  
Joseph G. Verbalis ◽  
Christopher S. Wilcox

Central angiotensin II (ANG II) regulates thirst. Because thromboxane A2-prostaglandin H2 (TP) receptors are expressed in the brain and mediate some of the effects of ANG II in the vasculature, we investigated the hypothesis that TP receptors mediate the drinking response to intracerebroventricular (icv) injections of ANG II. Pretreatment with the specific TP-receptor antagonist ifetroban (Ifet) decreased water intake with 50 ng/kg icv ANG II (ANG II + Veh, 7.2 ± 0.7 ml vs. ANG II + Ifet, 2.8 ± 0.8 ml; n = 5 rats; P < 0.001) but had no effect on water intake induced by hypertonic saline (NaCl + Veh, 8.4 ± 1.1 ml vs. NaCl + Ifet, 8.9 ± 1.8 ml; n = 5 rats; P = not significant). Administration of 0.6 μg/kg icv of the TP-receptor agonist U-46,619 did not induce drinking when given alone but did increase the dipsogenic response to a near-threshold dose of 15 ng/kg icv ANG II (ANG II + Veh, 1.1 ± 0.7 vs. ANG II + U-46,619, 4.5 ± 0.9 ml; n = 5 rats; P < 0.01). We conclude that central TP receptors contribute to the dipsogenic response to ANG II.


2005 ◽  
Vol 289 (3) ◽  
pp. R845-R850 ◽  
Author(s):  
Annegret Blume ◽  
Christian Undeutsch ◽  
Yi Zhao ◽  
Elena Kaschina ◽  
Juraj Culman ◽  
...  

In addition to rapid responses comprising increases in blood pressure, drinking, and stimulation of natriuresis, ANG II induces the expression of transcription factors (TF) in the central nervous system. The ANG II metabolite ANG III (ANG 2–8) has been demonstrated to exert physiological effects similar to those of ANG II. We aimed to determine 1) whether ANG III induces TF expression in the brain, 2) which ANG II (AT) receptor subtype is involved, and 3) whether the two peptides, ANG II and ANG III, differ in their efficacy to stimulate TF expression. ANG II (100 pmol), ANG III (100 pmol), or vehicle was injected into the lateral brain ventricle of conscious rats alone or in combination with the AT1 receptor antagonist losartan (10 nmol), the AT2 receptor antagonist PD-123319 (5 nmol), or the aminopeptidase inhibitor amastatin (10 nmol). Similar to ANG II, ANG III induced the expression of c-Fos, c-Jun, and Krox-24 in four brain regions, subfornical organ, median preoptic area, paraventricular nucleus, and supraoptic nucleus of the hypothalamus, with the same efficacy. This effect was AT1 receptor mediated. Pretreatment with amastatin reduced the expression of TF in response to ANG II, indicating that this expression is partly mediated by ANG III. Interestingly, the AT2 receptor antagonist PD-123319 alone slightly enhanced the expression of c-Fos, c-Jun, and Krox-24 in different populations of neurons of the paraventricular nucleus. These data indicate that different populations of neurons in the paraventricular nucleus are tonically inhibited by AT2 receptors under physiological conditions.


Sign in / Sign up

Export Citation Format

Share Document