Pressor response to compression of the ventrolateral medulla mediated by glutamate receptors.
نویسندگان
چکیده
The rostral ventrolateral medulla (RVLM) is considered a major center for the regulation of sympathetic and cardiovascular activities. Several clinical studies have indicated a possible causal relationship between neurovascular contact of the left RVLM and essential hypertension, and some investigators have suggested that the left RVLM is more sensitive to pulsatile compression than the right RVLM. Previously, we reported that pulsatile compression of the RVLM elevates arterial pressure by enhancing sympathetic outflow in rats; however, we have not investigated the laterality of the responses to the compression. In addition, it remains to be elucidated whether RVLM neurons are activated by compression and, if so, how they are activated. Therefore, we performed compression experiments in rats to investigate these issues. Pulsatile compression was performed on the unilateral RVLM with a pulsating probe in anesthetized and artificially ventilated rats. Pulsatile compression of the unilateral RVLM increased arterial pressure, heart rate, and sympathetic nerve activity. The pressor response to compression was inhibited significantly after local microinjection of glutamate receptor antagonists. Pulsatile compression of the RVLM increased Fos immunoreactivitiy, a marker of neuronal activation, within the nuclei of postsynaptic RVLM neurons. All results were observed symmetrically. The data indicate that the responses to pulsatile compression of the unilateral RVLM are similar on both sides. They also suggest that pulsatile compression of the RVLM increases sympathetic and cardiovascular activities by activating postsynaptic RVLM neurons through the stimulation of the local glutamate receptors in rats.
منابع مشابه
Glutaminergic receptors in rostral ventrolateral medulla mediate the cardiovascular responses to activation of bed nucleus of the stria terminalis in female rats
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متن کاملGABAergic receptors in rostral ventrolateral medulla mediates the cardiovascular responses to activation of bed nucleus of the stria terminalis in the female rat
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متن کاملGABAergic receptors in rostral ventrolateral medulla mediates the cardiovascular responses to activation of bed nucleus of the stria terminalis in the female rat
The bed nucleus of the stria terminalis (BST) is known to contain estrogen (E)- concentrating neurons. In addition, injections of E into BST have been reported to potentiate the sympathoinhibitory arterial pressure (AP) and heart rate (HR) responses elicited by glutamate (Glu) stimulation. In this study, the effect of GABA-A antagonist receptors, bicuculline methiodide (BMI), in the rostral ven...
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ورودعنوان ژورنال:
- Hypertension
دوره 33 5 شماره
صفحات -
تاریخ انتشار 1999