Cerebral circulation under normal and pathologic conditions
Publikation: Bidrag til tidsskrift › Review › Forskning › fagfællebedømt
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Cerebral circulation under normal and pathologic conditions. / Paulson, O B; Waldemar, G; Schmidt, J F; Strandgaard, S.
I: The American Journal of Cardiology, Bind 63, Nr. 6, 02.02.1989, s. 2C-5C.Publikation: Bidrag til tidsskrift › Review › Forskning › fagfællebedømt
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TY - JOUR
T1 - Cerebral circulation under normal and pathologic conditions
AU - Paulson, O B
AU - Waldemar, G
AU - Schmidt, J F
AU - Strandgaard, S
PY - 1989/2/2
Y1 - 1989/2/2
N2 - Autoregulation of the cerebral circulation is the regulating mechanism that keeps cerebral blood flow (CBF) constant within wide limits of arterial pressure. The lower limit is defined as the value of mean arterial pressure below which CBF decreases below the plateau, and the upper limit as the value of mean arterial pressure above which CBF increases above the plateau (60 and 150 mm Hg, respectively). Two possible mechanisms for autoregulation are discussed, myogenic response and metabolic regulation. Stimulation of the sympathetic nervous system and antagonism of the renin-angiotensin system modulate CBF autoregulation by shifting the entire curve toward higher or lower values of arterial pressure, respectively. The autoregulatory curve is shifted toward higher arterial pressures in chronic hypertension. Therefore, the tolerance to acute decreases in arterial pressure is impaired. Concomitantly, the tolerance of the brain to acute increases in arterial pressure is improved. This shift in the limits of autoregulation is due to structural and functional (hemodynamic) changes in the cerebral resistance vessels. These adaptive changes are partly reversible after chronic treatment with antihypertensive agents. The pathophysiology of autoregulation should be taken into consideration before drugs are used to decrease arterial pressure acutely.
AB - Autoregulation of the cerebral circulation is the regulating mechanism that keeps cerebral blood flow (CBF) constant within wide limits of arterial pressure. The lower limit is defined as the value of mean arterial pressure below which CBF decreases below the plateau, and the upper limit as the value of mean arterial pressure above which CBF increases above the plateau (60 and 150 mm Hg, respectively). Two possible mechanisms for autoregulation are discussed, myogenic response and metabolic regulation. Stimulation of the sympathetic nervous system and antagonism of the renin-angiotensin system modulate CBF autoregulation by shifting the entire curve toward higher or lower values of arterial pressure, respectively. The autoregulatory curve is shifted toward higher arterial pressures in chronic hypertension. Therefore, the tolerance to acute decreases in arterial pressure is impaired. Concomitantly, the tolerance of the brain to acute increases in arterial pressure is improved. This shift in the limits of autoregulation is due to structural and functional (hemodynamic) changes in the cerebral resistance vessels. These adaptive changes are partly reversible after chronic treatment with antihypertensive agents. The pathophysiology of autoregulation should be taken into consideration before drugs are used to decrease arterial pressure acutely.
KW - Animals
KW - Blood Flow Velocity
KW - Cerebrovascular Circulation
KW - Chronic Disease
KW - Homeostasis
KW - Humans
KW - Hypertension/physiopathology
U2 - 10.1016/0002-9149(89)90396-2
DO - 10.1016/0002-9149(89)90396-2
M3 - Review
C2 - 2643850
VL - 63
SP - 2C-5C
JO - Am. J. Cardiol.
JF - Am. J. Cardiol.
SN - 0002-9149
IS - 6
ER -
ID: 275323783