Further studies on the noradrenergic and the renin-angiotensin systems in the brain of the rat.
Previous investigations have shown that depletion of brain norepinephrine (NE) induced by chemical sympathectomy resulted in significant changes in the central renin-angiotensin system. The purpose of the present work was to increase the NE concentration in the central nervous system (CNS) in order to analyze its effect on the peptidergic complex and on the blood pressure (BP) levels. Treated rats were given the following drugs in the drinking water: 1-dopa (12 mg/rat/day), carbidopa (6 mg/rat/day) and pargyline (10 mg/rat/day) during 25 days. BP was determined, blood and cerebrospinal fluid (CSF) samples were obtained. The CNS was dissected into several areas. NE, angiotensinogen (AoC) and renin concentration (RC) were determined in the brain parenchyma; AoC was evaluated in CSF and plasma samples. Pharmacological treatment resulted in an hypotensive effect and, at the same time, an increase of NE in the CNS (about 100%; p less than 0.0005). These changes were accompanied by a significant decrease in the peripheral and central AoC. These results add new evidence to the postulated relationship between these two important regulatory systems involved in cardiovascular control.
Instituto de Investigaciones Cardiológicas, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
M L
ML
Kurnjek
M R
MR
Trolliet
L
L
Mikulic
N
N
Basso
D000804:Angiotensin II / Q000378:metabolism; D000808:Angiotensinogen / Q000378:metabolism; D000818:Animals; D001794:Blood Pressure; D001921:Brain / Q000502:physiology*; D002490:Central Nervous System / Q000378:metabolism; D004837:Epinephrine / Q000378:metabolism; D008297:Male; D009638:Norepinephrine / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000502:physiology*
D000808:Angiotensinogen; D000804:Angiotensin II; D012083:Renin; D009638:Norepinephrine; D004837:Epinephrine