- Aging Alters the Relative Contributions of the Sympathetic and Parasympathetic Nervous System to Blood Pressure Control in Women. [Journal Article]
- Autonomic support of blood pressure increases with age in humans. Large differences exist in the dose of trimethaphan (TMP) required for ganglionic blockade in young and older women. We asked whether differences in the dose of TMP required to achieve ganglionic blockade are because of differences in the relative contributions of the sympathetic and parasympathetic nervous system in control of blo…
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- The role of the paravertebral ganglia in human sympathetic neural discharge patterns. [Journal Article]
- The mechanisms affecting recruitment patterns of postganglionic sympathetic nerves remain unclear. The divergent and convergent preganglionic innervation patterns of postganglionic neurons and the presence of differently sized postganglionic nerves suggest that the ganglia may participate in modifying the discharge patterns of single sympathetic postganglionic neurons innervating the skeletal mus…
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- Neural control of blood pressure in women: differences according to age. [Journal Article]
- CONCLUSIONS: Our results suggest that there are differences in baroreflex control of muscle sympathetic nerve activity between young and older women, using the T50 and error signal analysis. This approach provides further information on autonomic control of blood pressure in women.
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- Influence of sympathetic nerve activity on aortic hemodynamics and pulse wave velocity in women. [Journal Article]
- Central (aortic) blood pressure, arterial stiffness, and sympathetic nerve activity increase with age in women. However, it is unknown if the age-related increase in sympathetic activity influences aortic hemodynamics and carotid-femoral pulse wave velocity (cfPWV), an index of central aortic stiffness. The goal of this study was to determine if aortic hemodynamics and cfPWV are directly influenc…
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- Aging enhances autonomic support of blood pressure in women. [Clinical Trial]
- The autonomic nervous system plays a central role in both acute and chronic blood pressure regulation in humans. The activity of the sympathetic branch of the autonomic nervous system is positively associated with peripheral resistance, an important determinant of mean arterial pressure in men. In contrast, there is no association between sympathetic nerve activity and peripheral resistance in wo…
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- Transient blood pressure changes affect the functional magnetic resonance imaging detection of cerebral activation. [Journal Article]
- Functional magnetic resonance imaging (fMRI) provides an indirect measure of cerebral activation that could be altered by factors directly affecting cerebral blood flow independent of changes in neuronal activation. Presently, we investigate how changes in blood pressure (BP) affect the activation detected with fMRI. fMRI scans were acquired in 33 rats under control conditions and following trans…
- Whether independent regulation of myocardial contractility and diastolic relaxation rate is possible? [Journal Article]Bull Exp Biol Med. 2003 Apr; 135(4):330-3.BE
- In acute experiments on cats neural inotropic and lusitropic reactions of the heart to enhancement of pre- and afterload were assessed by changes in contractility and relaxation indices, which were preliminary chosen for their maximum specificity and sensitivity. The control cardiac responses to increased pre- and afterload were measured after treatment with ganglionic blocker arfonad. The myogen…
- Contraction and relaxation indices in the study of neural inotropic and loositropic influences on the heart. [Journal Article]Bull Exp Biol Med. 2001 Dec; 132(6):1141-4.BE
- The possibility of using contraction and relaxation indices for evaluation of inotropic and loositropic influences on the heart was studied in experiments on cats. Increased pre- and afterload were used as the stimuli, which are simultaneously loading and reflexogenic. Under conditions of preserved innervation both stimuli elevated the indices selected according to the highest sensitivity/specifi…
- Comparison of different cardiac relaxation indices. [Journal Article]Bull Exp Biol Med. 2001 May; 131(5):416-20.BE
- Sensitivity (response to epinephrine infusion) and specificity (response to changes in pre- and afterload) of some cardiac relaxation indices were compared in acute experiments on cats treated with ganglionic blocker arfonad. Some new indices proposed by us provide better characteristics than widely used relaxation time constant (t) and maximum first derivative of the left ventricular pressure (-…
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- Mechanisms of respiratory sinus arrhythmia in patients with mild heart failure. [Clinical Trial]
- The high-frequency (HF) component of the heart rate variability (HRV) is regarded as an index of cardiac vagal responsiveness. However, when vagal tone is decreased, nonneural mechanisms could account for a significant proportion of the HF component. To test this hypothesis, we examined the HRV spectral power in 20 patients with mild chronic heart failure (CHF) and 11 controls before and during g…
- The diagnosis and management of hypertensive crises. [Review]
- Severe hypertension is a common clinical problem in the United States, encountered in various clinical settings. Although various terms have been applied to severe hypertension, such as hypertensive crises, emergencies, or urgencies, they are all characterized by acute elevations in BP that may be associated with end-organ damage (hypertensive crisis). The immediate reduction of BP is only requir…
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- Changes in cerebral blood flow accompanied with reduction of blood pressure treatment in patients with hypertensive intracerebral hemorrhages. [Randomized Controlled Trial]Neurol Res. 1997 Apr; 19(2):169-73.NR
- Blood pressure usually is reduced in patients with hypertensive intracerebral hemorrhage for the prevention of the expansion of the hematoma and recurrent hemorrhage in acute stage. However, disturbed autoregulation of cerebral circulation is expected, and decreased cerebral blood flow (CBF) caused by excessive hypotension has been pointed out. There are different mechanisms of action in hypotens…
- Comparison of nicotinic receptor binding and biotransformation of coniine in the rat and chick. [Journal Article]
- Coniine, an alkaloid from Conium maculatum (poison hemlock), is a known teratogen in many domestic species with maternal ingestion resulting in arthrogryposis of the offspring. We have previously shown that rats are not susceptible and rabbits only weakly susceptible to coniine-induced arthrogryposis. However, the chick embryo does provide a reproducible laboratory animal model of coniine-induced…
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- Metabolic and hormonal responses to induced hypotension for middle ear surgery. [Randomized Controlled Trial]
- We have investigated in 30 patients the metabolic and hormonal responses to middle ear surgery using induced hypotension to a mean arterial pressure of 55 mm Hg. A standardized anaesthetic technique of propranolol, thiopentone-vecuronium-isoflurane was used in all patients and hypotension induced with sodium nitroprusside, trimetaphan camsylate or additional isoflurane. All patients showed a clas…
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- Trimethaphan (Arfonad) control of hypertension and tachycardia during electroconvulsive therapy: a double-blind study. [Randomized Controlled Trial]
- CONCLUSIONS: Trimethaphan is safe, practical, and effective in the management of the hyperdynamic response to ECT. An i.v. bolus injection of 15 mg is more effective than 10 mg or 5 mg.
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- Ultra-high dose trimethaphan in an infant with severe hypertension. [Case Reports]J Toxicol Clin Toxicol. 1996; 34(2):227-9.JT
- Trimethaphan camsylate is a potent antihypertensive drug used to induce systemic arterial hypotension in patients undergoing major surgery and to treat severe systemic hypertension. The pharmacokinetics and pharmacodynamics of trimethaphan administered in the usual clinical dosages have been previously reported. The effects of trimethaphan when administered in very high doses of 500-1000 times th…
- Nitric oxide mediation of chemoregulation but not autoregulation of cerebral blood flow in primates. [Journal Article]
- The authors sought to develop a model for assessing in vivo regulation of cerebral vasoregulation by nitric oxide (NO), originally described as endothelial-derived relaxing factor, and to use this model to establish the role of NO in the regulation of cerebral blood flow (CBF) in primates. By using regional intraarterial perfusion, the function of NO in cerebral vasoregulation was examined withou…
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- Sympathetic nervous system effects on feline bladder wall compliance throughout continence. [Journal Article]
- The urinary bladder is a compliant organ, high compliance being essential for useful urine storage. The extent to which the sympathetic nervous system promotes the storage of urine by increasing bladder compliance is unclear. The aim of the present study was to determine the range of bladder volumes over which the sympathetic nervous system increased bladder wall compliance. In supine, anaestheti…
- The inhibitory effects of nicotinic antagonists on currents elicited by GABA in rat hippocampal neurons. [Journal Article]
- The nicotinic antagonists d-tubocurarine and trimethaphan camsylate competitively inhibit GABA-induced currents. Hexamethonium, mecamylamine and dihydro-beta-erythroidine, other nicotinic antagonists, do not affect GABA-elicited currents. The trimethaphan effect is completely reversed by a putative convulsant receptor antagonist, alpha-isopropyl-alpha-methyl-gamma-butyrolactone, which implies tha…
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- [The cerebral blood circulation during hypokinesia under the influence of hypercapnia, hypotonia, GABA and neurosensory stimulation]. [Journal Article]Eksp Klin Farmakol. 1995 Jul-Aug; 58(4):23-5.EK
- We studied the formation of vasomotor reflexes in hypokinesia and responses of the brain vessels to the action of GABA, hypotension, and hypercapnia. We found that the response of the brain vessels to GABA is delayed and the mechanisms which supported an adequate cerebral vasculation are distorted in hypotension. At the same time the disturbance of the reflectory reaction of the brain vessels in …
- Effects of stobadine on survival, histopathologic outcome and acid-base status after global brain ischemia in dogs. [Journal Article]J Hirnforsch. 1995; 36(3):365-78.JH
- Present study is designed to examine an effect of Stobadine, a new cell-protective agent with antiarrhythmic properties, on survival, electron microscopic changes in microvasculatory bed of selected brain areas and acid-base parameters of arterial blood after global brain ischemia and reperfusion. Forty dogs (weighting 6 to 15 kg) were anesthetized using pentobarbital i.v. (5%, 35 mg/kg). An intu…
- Cardiovascular effects of NaCl microinjections into the nucleus of the solitary tract. [Journal Article]
- The nucleus of the solitary tract (NTS) was systematically explored in the alpha-chloralose-anesthetized rat for sites that elicited changes in mean arterial pressure (MAP) and heart rate (HR) during microinjections (20 nl) of phosphate-buffered saline (PBS; pH 7.2-7.4) or NaCl solutions containing various concentrations of NaCl (104-326 mM). Decreases in MAP (range 7-83 mmHg) and HR (range 10-70…
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- [A case of torsades de pointes probably caused by trimetaphan intoxication]. [Case Reports]
- A 42-year-old male was hospitalized in the surgical ward for abdominal pain due to stenosis of the splenic flexure of the colon and abscess around the stenosis. After segmental colectomy, the patient received intravenous continuous infusion of trimetaphan (Arfonad) to control his blood pressure. Twenty hours later, he developed bradycardia and hypotension followed by syncope. An electrocardiogram…
- In vitro pharmacologic characterization of a cholinergic receptor on outer hair cells. [Journal Article]
- Acetylcholine (ACh) is the major neurotransmitter released from the efferent fibers in the cochlea onto the outer hair cells (OHCs). The type of ACh receptor on OHCs and the events subsequent to receptor activation are unclear. Therefore we studied the effect of agonists and antagonists of the ACh receptor on isolated OHCs from the guinea pig. OHCs were recorded from in whole cell voltage and cur…
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- Systemic hypertension induced by aortic cross-clamping: detrimental effects of direct smooth muscle relaxation compared with ganglionic blockade. [Journal Article]J Vasc Surg. 1994 Apr; 19(4):707-16.JV
- CONCLUSIONS: The attenuation of clamp-induced hypertension by nitroprusside is associated with a dramatic increase in CO and cardiac work whereas the use of trimethaphan camsylate is not. The use of this ganglionic blocker may be more appropriate in this setting.
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- Model for the assessment of heart period and arterial pressure variability interactions and of respiration influences. [Journal Article]
- A model which assesses the closed-loop interaction between heart period (HP) and arterial pressure (AP) variabilities and the influence of respiration on both is applied to evaluate the sources of low frequency (LF approximately 0.1 Hz) and high frequency (HF, respiratory rate approximately 0.25 Hz) in conscious dogs (n = 18) and humans (n = 5). A resonance of AP closed-loop regulation is found t…
- The paradoxical blood pressure-flow relationship in the brain with an arteriovenous malformation. [Journal Article]
- The responses of regional cerebral blood flow (CBF) to decrease in arterial blood pressure were studied in eight patients with arteriovenous malformations using the Xe-133 inhalation method. Measurements were performed twice for each study; before and during hypotension induced by trimethaphan camsylate (Arfonad). In all cases, there were regions where cerebral blood flow increased remarkably in …
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- Effect of glutamate stimulation of bed nucleus of the stria terminalis on arterial pressure and heart rate. [Journal Article]
- Experiments were done in the chloralose-anesthetized, paralyzed, and artificially ventilated rat to determine the cardiovascular responses elicited during chemical stimulation of bed nucleus of the stria terminalis (BST) and to investigate the components of the peripheral autonomic nervous system that mediate these responses. Neurons in BST were selectively stimulated by the microinjection (10-20…
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- [Stereotactic evacuation of massive hypertensive intracerebral hemorrhage]. [Journal Article]No Shinkei Geka. 1993 Jun; 21(6):509-12.NS
- Six patients with massive hypertensive intracerebral hemorrhage and showing progression of consciousness-disturbance were treated by CT-guided stereotactic surgery. Serious complications or the age of these patients prevented evacuation of the hematomas by craniotomy under general anesthesia. The increase in the size of the intracerebral hematoma suggested by the progression of the consciousness-…
- A novel cholinergic receptor mediates inhibition of chick cochlear hair cells. [Journal Article]
- The central nervous system provides feedback regulation at several points within the peripheral auditory apparatus. One component of that feedback is inhibition of cochlear hair cells by release of acetylcholine (ACh) from efferent brainstem neurons. The mechanism of hair cell inhibition, and the character of the presumed cholinergic receptor, however, have eluded understanding. Both nicotinic an…