July 1, 1979Hypertension
Clonidine and carotid baroreflex in essential hypertension.
Why the study?
Does intravenous clonidine potentiate carotid baroreflexes to reduce blood pressure in patients with essential hypertension?
Population
16 patients with essential hypertension
Comparison
Intravenous administration of 150 microgram and… vs Baseline (before clonidine administration)
Design
Other
Authors
Discussion
Loading...
Member takes
Implication
Clonidine lowers BP without baroreflex potentiation in humans; challenges animal model mechanisms and leaves clinical translation open.
Key Points
- To determine whether the hypotensive action of clonidine in essential hypertension occurs through the potentiation of carotid sinus baroreceptor reflexes.
- Investigated 16 patients with essential hypertension using arterial catheterization to measure blood pressure and heart rate.
- Manipulated carotid sinus baroreceptor activity using the neck chamber technique before and after intravenous administration of 150 µg and 300 µg of clonidine.
- Quantified baroreflex responses by calculating the linear regression slopes relating changes in carotid transmural pressure to alterations in mean arterial pressure and R-R interval.
- Clonidine administration induced a marked reduction in mean arterial pressure (-26 ± 3 mm Hg) and a modest decrease in heart rate (-5 ± 1 beats/min).
- No evidence of baroreceptor potentiation on blood pressure control was observed after clonidine administration, with only infrequent and slight potentiation of baroreflex control over heart rate.
Structured PICO
Does intravenous clonidine potentiate carotid baroreflexes to reduce blood pressure in patients with essential hypertension?
P
Population
16 patients with essential hypertension
I
Intervention
Intravenous administration of 150 microgram and 300 microgram of clonidine
C
Comparator
Baseline (before clonidine administration)
O
Outcome
Changes in mean arterial pressure and R-R interval in response to alterations in carotid sinus baroreceptor activitysurrogate
Clonidine exerts a pronounced hypotensive effect in humans without potentiating baroreceptor influence on blood pressure, challenging the mechanism suggested by animal models.
Cite This Study
Mancia et al. (1979) studied this question.