In:
Journal of Neuroendocrinology, Wiley, Vol. 31, No. 4 ( 2019-04)
Kurzfassung:
Angiotensin II ( Ang II ) acts on Ang II type 1 ( AT 1) receptors located in the organum vasculosum and subfornical organ ( SFO ) of the lamina terminalis as a main facilitatory mechanism of sodium appetite. The brain serotonin (5‐ HT ) system with soma located in the dorsal raphe nucleus ( DRN ) provides a main inhibitory mechanism. In the present study, we first investigated the existence of Ang II AT 1 receptors in serotonergic DRN neurones. Then, we examined whether whole body sodium depletion affects the gene expression of the AT 1a receptor subtype and the presumed functional significance of AT 1 receptors. Using confocal microscopy, we found that tryptophan hydroxylase‐2 and serotonin neurones express AT 1 receptors in the DRN . Immunofluorescence quantification showed a significant reduction in 5‐ HT content but no change in AT 1 receptor expression or AT 1/5‐ HT colocalisation in the DRN after sodium depletion. Whole body sodium depletion also significantly increased Agtr1a mRNA expression in the SFO and DRN . Oral treatment with the AT 1 receptor antagonist losartan reversed the changes in Agtr1a expression in the SFO but not the DRN . Losartan injection into either the DRN or the mesencephalic aqueduct had no influence on sodium depletion‐induced 0.3 mol L ‐1 NaCl intake. The results indicate the expression of Agtr1a mRNA in the DRN and SFO as a marker of sodium depletion. They also suggest that serotonergic DRN neurones are targets for Ang II . However, the function of their AT 1 receptors remains elusive.
Materialart:
Online-Ressource
ISSN:
0953-8194
,
1365-2826
DOI:
10.1111/jne.2019.31.issue-4
Sprache:
Englisch
Verlag:
Wiley
Publikationsdatum:
2019
ZDB Id:
2007386-0
