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Ontogeny of angiotensin II type 1 receptor mRNAs in fetal and neonatal rat brain
Author(s) -
Nuyt Anne Monique,
Lenkei Zsolt,
Corvol Pierre,
Palkovits Miklós,
LlorensCortés Catherine
Publication year - 2001
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.1379
Subject(s) - biology , endocrinology , medicine , periventricular nucleus , subfornical organ , area postrema , in situ hybridization , hypothalamus , nucleus ambiguus , median preoptic nucleus , dorsal motor nucleus , angiotensin ii , solitary tract , central nervous system , gene expression , medulla oblongata , arcuate nucleus , vagus nerve , stimulation , gene , blood pressure , biochemistry
Studies have demonstrated a specific function of the angiotensin II (Ang II) type 1 receptor (AT 1 ) in regulation of adult central cardiovascular, fluid, and pituitary hormone release and a predominant role of the renin‐angiotensin system in fetal and neonatal cardiovascular homeostasis. The pattern of brain AT 1 mRNA expression during fetal and neonatal development is currently unknown. We used radiolabeled cRNA probes for in situ hybridization histochemistry to determine the ontogenic development of the two AT 1 subtypes (AT 1a and AT 1b ) mRNA in rat brain, from 11 days of gestation (E11) to 28 days after birth (P28). No AT 1b mRNA was detected in the developing brain, whereas AT 1a mRNA was first detected at E19. The age at which AT 1a mRNA is first detected varied among different brain areas and expression predominates in areas involved in fluid homeostasis, pituitary hormone release, and cardiovascular regulation, where it persists until P28. AT 1a mRNA expression is present from E19 onward in the median preoptic nucleus, the vascular organ of the lamina terminalis, the paraventricular nucleus, the periaqueductal gray, the nucleus raphe pallidus, the motor facial nucleus, and very weakly in the nucleus of the solitary tract and the ambiguus nucleus, and at E21 in the subfornical organ, the anterior olfactory nucleus and the piriform cortex. AT 1a mRNA expression is present after birth in many regions, including the preoptic and lateral hypothalamic areas, the area postrema and medullary reticular nuclei. In conclusion, during brain development, expression of AT 1a mRNA, appears in late gestation at E19, predominantly in forebrain areas involved in fluid homeostasis and cardiovascular regulation. In contrast, AT 1a mRNA expression is absent or present only in very small amounts until after birth in many medullary nuclei, known to play an important role in cardiovascular modulation. Our results suggest that, in perinatal life, AT 1a is involved in fluid and perhaps cardiovascular homeostasis and that the role of Ang II in modulating medullary cardiovascular centers matures later in postnatal life. J. Comp. Neurol. 440:000–000, 2001. J. Comp. Neurol. 440:192–203, 2001. © 2001 Wiley‐Liss, Inc.