Intra-carotid angiotensin II activates tyrosine hydroxylase-expressing rostral ventrolateral medulla neurons following blood-brain barrier disruption in rats

Abstract

Angiotensin II (Ang II) in the periphery and within the brain plays important roles in blood pressure control. Circulating angiotensin is normally excluded from the brain by the blood-brain barrier (BBB), but there is evidence that in some diseases there is disruption of the BBB that could allow circulating Ang II to access nuclei from which it is normally excluded, such as the rostral ventrolateral medulla (RVLM). We therefore investigated whether disruption of the BBB leads to increased activation by circulating Ang II of tyrosine hydroxylase (TH)-containing neurons in the RVLM. In anaesthetised rats, in which the BBB was disrupted with intracarotid hypertonic mannitol (1.6. M, 2. mL/kg), ..