Vascular tissue renin-angiotensin system in hypertensive humans.
OBJECTIVE
To obtain direct evidence for and evaluate functional aspects of the vascular tissue renin-angiotensin system.


METHODS
The local release of renin and angiotensin II was studied in forearm and coronary vascular beds of hypertensive hospitalized patients. The interaction between the vascular tissue renin-angiotensin system and sympathetic neurotransmission was also evaluated.


RESULTS
Local beta-adrenoceptor stimulation released active and inactive renin and angiotensin II from forearm vessels, indicating the presence of a vascular tissue renin-angiotensin system in essential hypertensives. Local production of active renin and angiotensin II was closely correlated with circulating renin levels, suggesting that this vascular tissue renin-angiotensin system is at least partly dependent on uptake of renin from the circulating renin-angiotensin system. The local active renin and angiotensin II production was rapidly exhausted; this might represent a short-term control mechanism. Locally generated angiotensin II increased sympathetic vasoconstriction through the presynaptic release of noradrenaline and this effect was mediated by beta-adrenoceptor stimulation. Infusions of adenosine promoted the release of active renin and angiotensin II from the forearm and the coronary vessels.
Taddei
S
S
Cattedra di Medicina Interna, University of Pisa, Italy.
Salvetti
A
A
D000241:Adenosine; D000804:Angiotensin II / Q000378:metabolism; D000806:Angiotensin-Converting Enzyme Inhibitors; D003331:Coronary Vessels / Q000378:metabolism; D005542:Forearm / Q000098:blood supply; D006801:Humans; D006973:Hypertension / Q000378:metabolism / Q000503:physiopathology*; D007545:Isoproterenol; D009638:Norepinephrine / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000502:physiology; D012083:Renin / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000502:physiology*; D012504:Saralasin
D000806:Angiotensin-Converting Enzyme Inhibitors; D011943:Receptors, Adrenergic, beta; D000804:Angiotensin II; D012083:Renin; D012504:Saralasin; D000241:Adenosine; D007545:Isoproterenol; D009638:Norepinephrine