Neurosteroid modulation of arterial baroreflex function in the rostral ventrolateral medulla.
Summary of "Neurosteroid modulation of arterial baroreflex function in the rostral ventrolateral medulla."
Through both genomic and nongenomic actions, ovarian hormones and their metabolites have significant effects on the central nervous system to modulate a variety of regulatory systems, including the cardiovascular system. The major metabolite of progesterone, 3α-hydroxy-dihydroprogesterone, is the most potent endogenous positive modulator of GABA(A) receptors known and central nervous system levels of this progesterone metabolite fluctuate with the ovarian cycle and are elevated in pregnant animals. Pregnancy is associated with attenuated arterial baroreflex sympathoexcitation and increased tonic GABAergic inhibition of the rostral ventrolateral medulla (RVLM) likely contributes. The current experiments were performed to determine if the effects of pregnancy on arterial baroreflex control of renal sympathetic nerve activity could be mimicked by microinjection of the neuroactive progesterone metabolite into the RVLM. Compared to control values, 15min after microinjection of 3α-hydroxy-dihydroprogesterone into the RVLM (n=10), baseline renal sympathetic nerve activity was decreased to 82% of baseline, and the range (157±10 to 131±11%) and maximum nerve activity (164±9 to 136±12%) for the arterial baroreflex curves were decreased. In contrast, microinjection of the inactive isomer, 3β-hydroxy-dihydroprogesterone into the RVLM (n=9), had no effect on baseline nerve activity or the arterial baroreflex nerve activity range or maximum. Thus, although multiple mechanisms likely contribute to pregnancy associated changes in baroreflex function, these experiments suggest that increased levels of 3α-hydroxy-dihydroprogesterone in the RVLM might contribute.
This article was published in the following journal.
Name: Autonomic neuroscience : basic & clinical
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/21071286
- DOI: http://dx.doi.org/10.1016/j.autneu.2010.10.002
This study investigated the effects of angiotensin II (Ang II) on slow and rapid baroreflex responses of barosensitive bulbospinal neurons in the rostral ventrolateral medulla (RVLM) in urethane-anest...
Exercise training reduces sympathetic activity in hypertensive humans and rats. We hypothesized that the swimming exercise would change the neurotransmission in the rostral ventrolateral medulla (RVLM...
A dramatic bradycardia is induced by underwater submersion in vertebrates. The location of parasympathetic preganglionic cardiac motor neurons driving this aspect of the diving response was investigat...
Diabetes is a major world health problem. Growing evidence from both clinical trials and animal experiments has clearly confirmed that arterial baroreflex dysfunction is a feature of type 1 diabetes,...
The endogenous sulfur-containing amino acid L-cysteine injected into the cerebrospinal fluid space of the cisterna magna increases arterial blood pressure (ABP) and heart rate (HR) in the freely movin...
This randomized controlled trial will examine whether behavioral neurocardiac training with heart rate variability biofeedback (BNT) augments reduction in ambulatory daytime and 24-hour SB...
Since Tai Chi Chuan (TCC) training has been shown to be beneficial to the cardiopulmonary function of the subject, TCC might have a beneficial effect on the pulmonary function, autonomic n...
The aims of this study are to provide pharmacokinetic-pharmacodynamic data to quantify the analgesic and side effect profiles of epidural methadone, fentanyl and morphine. The investigator...
The purpose of this study is to assess the effects of the Celacade™ system in patients with intermittent claudication.
Aliskiren is a novel renin inhibitor approved for the treatment of hypertension. The effect of aliskiren on arterial stiffness, inflammation and oxidative stress has not been fully investi...
Medical and Biotech [MESH] Definitions
A response by the BARORECEPTORS to increased BLOOD PRESSURE. Increased pressure stretches BLOOD VESSELS which activates the baroreceptors in the vessel walls. The net response of the CENTRAL NERVOUS SYSTEM is a reduction of central sympathetic outflow. This reduces blood pressure both by decreasing peripheral VASCULAR RESISTANCE and by lowering CARDIAC OUTPUT. Because the baroreceptors are tonically active, the baroreflex can compensate rapidly for both increases and decreases in blood pressure.
Loss of detectable antigen from the surface of a cell after incubation with antibodies. This is one method in which some tumors escape detection by the immune system. Antigenic modulation of target antigens also reduces the therapeutic effectiveness of treatment by monoclonal antibodies.
The inner portion of the adrenal gland. Derived from ECTODERM, adrenal medulla consists mainly of CHROMAFFIN CELLS that produces and stores a number of NEUROTRANSMITTERS, mainly adrenaline (EPINEPHRINE) and NOREPINEPHRINE. The activity of the adrenal medulla is regulated by the SYMPATHETIC NERVOUS SYSTEM.
Thickening and loss of elasticity of the walls of medium and large muscular ARTERIES with lesions in the innermost layer of the artery (ARTERIAL INTIMA). This disease process of atherogenesis includes the retention of cholesterol-rich LIPOPROTEINS and their binding to PROTEOGLYCANS in the arterial intima, generation of proinflammatory molecules that recruit MACROPHAGES to the subendothelial space, formation of FOAM CELLS, and eventual calcification of the arterial wall. These arterial plaques (atheromas) contain CARBOHYDRATES; BLOOD; and CALCIUM.
Blocking of a blood vessel by CHOLESTEROL-rich atheromatous deposits, generally occurring in the flow from a large artery to small arterial branches. It is also called arterial-arterial embolization or atheroembolism which may be spontaneous or iatrogenic. Patients with spontaneous atheroembolism often have painful, cyanotic digits of acute onset.