[Increased vasodilation response to the stimulation of low pressure mechanoreceptors in borderline hypertension].
Passive lifting of the lower limbs (antitilt) is a simple manoeuvre which stimulates low-pressure mechanoreceptors. Patients with borderline hypertension have an alteration of the arterial baroreflex modulated by an increased inhibitory effect of cardiopulmonary mechanoreceptors on vasomotor centres. The repercussions of antitilt on mean arterial pressure (MAP), heart rate (HR) and blood flow rate in the forearm (FRFA) were studied in 30 male subjects aged 18 to 25 years: 14 with untreated borderline hypertension ("patients") and 16 controls. FRFA was measured with a plethysmograph by means of a mercury constraint gauge. MAP was recorded during exploration with a DINAMAP instrument. The parameters were measured in recumbent position, then within minutes of the antitilt manoeuvre. In recumbent position the differences between patients and controls were: MAP 94.7 +/- 6 vs 84.7 +/- 7 mmHg (p less than 0.001); HR 76 +/- 13 vs 63 +/- 9 beats/min (p less than 0.01); FRFA 4.6 +/- 1.5 vs 3.5 +/- 1.4 ml/min/100 ml (p less than 0.05). Following antitilt, MAP and HR remained unchanged in the two groups, but there was a significant increase of FRFA in both controls (+ 0.6 +/- 0.2 ml/min/100 ml; p less than 0.02) and patients (+ 1.3 +/- 0.2 ml/min/100 ml; p less than 0.001). This increase was significantly greater in patients than in controls (p less than 0.05). This study shows that antitilt produces an increase of blood flow rate in the forearm that is more pronounced in patients with borderline hypertension than in controls. The stability of MAP and HR is in favour of non-actuation of the high-pressure arterial baroreflex.(ABSTRACT TRUNCATED AT 250 WORDS)
Girerd
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X
Centre de diagnostic, hôpital Broussais, Paris.
Chanudet
X
X
Clement
R
R
Larroque
P
P
London
G
G
Safar
M
M
D000328:Adult; D001783:Blood Flow Velocity; D001794:Blood Pressure; D005542:Forearm / Q000098:blood supply; D006339:Heart Rate; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008465:Mechanoreceptors / Q000503:physiopathology*; D011187:Posture; D014664:Vasodilation
Augmentation de la réponse vasodilatatrice à la stimulation des mécanorécepteurs à basse pression chez l'hypertendu limite.