Efficacy of clonidine in patients with essential hypertension with neurovascular contact of the rostral ventrolateral medulla

Abstract

The rostral ventrolateral medulla (RVLM) is an important center for regulation of sympathetic nerve activity. Several clinical studies have suggested an association between neurovascular contact (NVC) of RVLM and essential hypertension. Microvascular decompression (MVD) of RVLM decreases blood pressure (BP) in hypertensive patients with NVC of this region. Therefore, MVD could be a useful therapeutic strategy to reduce BP in these patients. However, as MVD is an invasive procedure, it is worthy to seek useful antihypertensive agents for hypertensive patients with NVC. It is reported that sympathetic nerve activity is elevated in patients with hypertension accompanied by NVC of RVLM. It is anticipated that sympatholytic agents could be effective in lowering BP in these patients. In this study, we investigated the efficacy of clonidine, an a2 adrenergic agonist, in essential hypertensives with NVC of RVLM. Thirty consecutive essential hypertensive patients with NVC and 30 consecutive essential hypertensive patients without contact were treated with clonidine for 4 weeks, and decreases in BP and plasma norepinephrine levels were compared between the two groups. Decreases in BP and plasma norepinephrine levels were significantly greater in patients with NVC than in those without contact. These results suggest that clonidine exhibits significantly greater reductions of BP and sympathetic nerve activity in essential hypertensive patients with NVC compared with those without contact of the rostral ventrolateral medulla.

Observations of Changes of Blood Pressure Before and after Neurosurgical Decompression in Hypertensive Patients with Different Types of Neurovascular Compression of Brain Stem

“…In a recent Japanese study it has been reported, similar to many previous studies, that prevalence of NVPC of the RVLM was significantly higher in the group of patients with primary HT (35%) than in the normotensive group (13%) (p<0.05) [3,4,14,15,16,17,18]. A recent study using high-resolution MRI scans with 1 mm slices showed that the frequency of NVPC of the RVLM was clearly and significantly higher in patients with primary HT (73.5%) than in patients with secondary HT (12.5%) [19].…”

Effect of Microvascular Decompression of the Vagus Root Entry/Exit Zone on Blood Pressure in Patients with Hemifacial Spasm Associated with Essential Hypertension: A Retrospective Clinical Analysis

“…The anatomy and imaging data of patients with hypertension also showed that the left side of the ventrolateral medulla oblongata and vagus nerve REZ offending vessels are more than the right. 21 22 However, we found that the change in BP between 3 days before and 7 days and 6 months after MVD was not significantly associated with laterality of pathology, which refutes the idea that only the left side is involved in BP regulation. This supports the opinion proposed by Sindou et al, 4 which indicates that both the left and right ventrolateral medulla and vagus nerve REZ are involved in BP regulation.…”

Sympathetic Nervous System Dysfunction in Multiple Sclerosis, Linking Neurodegeneration to a Reduced Response to Therapy

“…The effect of these drugs on the course of MS may vary depending on their selectivity toward and ARs. For example, the 2 AR agonist, Clonidine, reduces NE plasma levels in hypertensive patients [68]. Since it is a centrally-acting agent, Clonidine-induced activation of CNS 2 ARs may promote CNS neurodegenerative processes through the activation of MAP kinases [9,10].…”