scholarly journals Relative contributions of the thalamus and the paraventricular nucleus of the hypothalamus to the cardiac sympathetic afferent reflex

2013 ◽  
Vol 305 (1) ◽  
pp. R50-R59 ◽  
Author(s):  
Bo Xu ◽  
Hong Zheng ◽  
Kaushik P. Patel
Keyword(s):  
Arterial Pressure ◽  
Paraventricular Nucleus ◽  
Single Unit ◽  
Thalamic Nucleus ◽  
Control Group ◽  
Unit Recording ◽  
Hypothalamic Nuclei ◽  
Mediodorsal Thalamic Nucleus ◽  
Cardiac Sympathetic Afferent Reflex ◽  
Intact Rats

The cardiac sympathetic afferent reflex (CSAR) is induced by stimulating the cardiac sympathetic afferents, which evokes increases in sympathetic outflow and arterial pressure. In the present study, we attempted to identify the contribution of thalamic and hypothalamic nuclei involved in the CSAR. First, we observed that there was an increase in the number of c-Fos-labeled cells in the paraventricular nucleus (PVN) (190 ± 18 vs. 101 ± 15; P < 0.05), the paraventricular nucleus of the thalamus (PVT) (239 ± 23 vs. 151 ± 15; P < 0.05), and the mediodorsal thalamic nucleus (MD) (92 ± 9 vs. 63 ± 6; P < 0.05) following epicardial application of bradykinin (BK) compared with the control group ( P < 0.05). Second, using extracellular single-unit recording, we found 25% of spontaneously active neurons in the thalamus were stimulated by epicardial application of BK or capsaicin in intact rats. However, 24% of spontaneously active neurons in the thalamus were still stimulated by epicardial application of BK or capsaicin despite vagotomy and sinoaortic denervation. None of the neurons in the thalamus responded to baroreflex changes in arterial pressure, induced by intravenous injection of phenylephrine or sodium nitroprusside. The CSAR was inhibited by microinjection of muscimol or lidocaine into the PVN. However, it was not inhibited or blocked by microinjection of muscimol or lidocaine into the thalamus. Taken together, these data suggest that the thalamus, while activated, is not critical for autonomic adjustments in response to activation of the CSAR. On the other hand, the PVN is critically involved in the central pathway of the CSAR.

scholarly journals Time Efficiency of Digitally and Conventionally Produced Single-Unit Restorations

2021 ◽  
Vol 9 (6) ◽  
pp. 62
Author(s):  
Sofia Stromeyer ◽  
Daniel Wiedemeier ◽  
Albert Mehl ◽  
Andreas Ender
Keyword(s):  
Single Unit ◽  
Operating Time ◽  
In Vitro Study ◽  
Working Time ◽  
Control Group ◽  
Similar Amount ◽  
Scan Design ◽  
Time Efficiency ◽  
Dental Professional

The purpose of this in vitro study was to compare the time efficiency of digital chairside and labside workflows with a conventional workflow for single-unit restorations. The time efficiency in this specific sense was defined as the time, which has to be spent in a dental office by a dental professional performing the relevant steps. A model with interchangeable teeth on position 36 was created. These teeth were differently prepared, responding to several clinical situations to perform single-unit restorations. Different manufacturing techniques were used: For the digital workflows, CEREC Omnicam (CER) and Trios 3 (TN/TI) were used. The conventional workflow, using a dual-arch tray impression technique, served as the control group. For the labside workflow (_L) and the conventional impression procedure (CO), the time necessary for the impressions and temporary restorations was recorded and served as operating time. The chairside workflow time was divided by the time for the entire workflow (_C) including scan, design, milling and finishing the milled restoration, and in the actual working time (_CW) leaving out the chairside milling of the restoration. Labside workflow time ranged from 9 min 27 s (CER_L) to 12 min 41 s (TI_L). Entire chairside time ranged from 43 min 35 s (CER_C) to 58 min 43 s (TI_C). Pure chairside working time ranged from 15 min 21 s (CER_CW) to 23 min 17 s (TI_CW). Conventional workflow time was 10 min 39 s (CO) on average. The digital labside workflow and the conventional workflow require a similar amount of time. The digital chairside workflow is more time consuming.

scholarly journals Pressure-clamped single-fiber recording technique: A new recording method for studying sensory receptors

2020 ◽  
Vol 16 ◽  
pp. 174480692092785 ◽  
Author(s):  
Mayumi Sonekatsu ◽  
Hiroshi Yamada ◽  
Jianguo G Gu
Keyword(s):  
Nerve Fiber ◽  
Single Unit ◽  
Single Fiber ◽  
Single Unit Recording ◽  
Sensory Receptors ◽  
Unit Recording ◽  
Recording Technique ◽  
C Fibers ◽  
Recording Method ◽  
Single Nerve

An electrophysiological technique that can record nerve impulses from a single nerve fiber is indispensable for studying modality-specific sensory receptors such as low threshold mechanoreceptors, thermal receptors, and nociceptors. The teased-fiber single-unit recording technique has long been used to resolve impulses that are likely to be from a single nerve fiber. The teased-fiber single-unit recording technique involves tedious nerve separation procedures, causes nerve fiber impairment, and is not a true single-fiber recording method. In the present study, we describe a new and true single-fiber recording technique, the pressure-clamped single-fiber recording method. We have applied this recording technique to mouse whisker hair follicle preparations with attached whisker afferents as well as to skin-nerve preparations made from mouse hindpaw skin and saphenous nerves. This new approach can record impulses from rapidly adapting mechanoreceptors (RA), slowly adapting type 1 mechanoreceptors (SA1), and slowly adapting type 2 mechanoreceptors (SA2) in these tissue preparations. We have also applied the pressure-clamped single-fiber recordings to record impulses on Aβ-fibers, Aδ-fibers, and C-fibers. The pressure-clamped single-fiber recording technique provides a new tool for sensory physiology and pain research.

On the search for the vocal pattern generator. A single-unit recording study

Neuroreport ◽  
2000 ◽  
Vol 11 (9) ◽  
pp. 2031-2034 ◽  
Author(s):  
Frank Düsterhöft ◽  
Udo Häusler ◽  
Uwe Jürgens
Keyword(s):  
Single Unit ◽  
Pattern Generator ◽  
Single Unit Recording ◽  
Unit Recording

scholarly journals The Effects of Vibroacoustically Induced Microvibrations on Arterial Blood Pressure and Oxidative Stress in Rats

2014 ◽  
Vol 15 (2) ◽  
pp. 83-88
Author(s):  
Dusko Kornjaca ◽  
Vladimir Zivkovic ◽  
Nevena Barudzic ◽  
Vladimir Jakovljevic ◽  
Dragan Djuric
Keyword(s):  
Oxidative Stress ◽  
Arterial Pressure ◽  
Systolic Arterial Pressure ◽  
Control Group ◽  
Oxidative Stress Markers ◽  
Sound Waves ◽  
Initial Value ◽  
The Third ◽  
Stress Markers ◽  
Arterial Blood

ABSTRACT Vibroacoustics, a scientific field that has been intensively studied for the last thirty years, uses the properties of sound waves (infrasound, ultrasound, noise and music) to induce vibrations that, like a sound wave, may have both useful and harmful effects. Th e aim of this study was to examine the effects of vibroacoustically induced microvibrations on arterial blood pressure and markers of oxidative stress in the blood. Th e experiments were performed on Wistar male rats that had a 180-200 g body mass and were divided into control and experimental groups (6 rats in each). In the experimental group, microvibrations were induced using the Vitafon vibroacoustic apparatus (Vitafon, St. Petersburg, Russian Federation), which delivers sound waves of varying frequencies by a process called “phoning”. Up to 60 minutes of phoning time was delivered to the kidney and liver using 4 diff erent regimens that included a 5-minute stabilisation time; up to four 10-minute phoning regimens, with 5-minute breaks between each single regimen, at a 30 Hz-18000 kHz frequency range;, and 2.8 μm-12.3 μm microwave amplitudes. After the completion of a phoning regimen, animals were sacrificed and the oxidative stress markers were measured in blood samples (O2-, H2O2, nitrites, lipid peroxidation index, superoxide dismutase, catalase, and glutathione) and compared with the values of markers in the control group. Systolic arterial pressure was analysed after the acute application of up to four diff erent regimens of vibroacoustic microvibrations. Systolic arterial pressure decreased significantly during the administration of the second regimen in comparison to the control group. Systolic arterial pressure returned, almost completely, to the initial value after the administration of the third and fourth regimens. Th ere was no significant change in diastolic arterial pressure after the acute administration of up to four different regimens, although the pressure decreased slightly after the first and second regimens and returned to the initial value during the administration of the third and fourth regimens. Analysis of oxidative stress markers showed a statistically significant change in the catalase level. No statistically significant differences were found in the other oxidative stress markers analyzeanalysed. Further research is needed to clarify the physiological effects of low compared to high frequencies of vibroacoustically induced microvibrations and their possible therapeutic significance.

Hypothalamic paraventricular nucleus is critical for renal vasoconstriction elicited by elevations in body temperature

2008 ◽  
Vol 294 (2) ◽  
pp. F309-F315 ◽  
Author(s):  
Joo Lee Cham ◽  
Emilio Badoer
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Renal Blood Flow ◽  
Core Temperature ◽  
Paraventricular Nucleus ◽  
Hypothalamic Paraventricular Nucleus ◽  
Body Core Temperature ◽  
Control Group ◽  
Body Core

Redistribution of blood from the viscera to the peripheral vasculature is the major cardiovascular response designed to restore thermoregulatory homeostasis after an elevation in body core temperature. In this study, we investigated the role of the hypothalamic paraventricular nucleus (PVN) in the reflex decrease in renal blood flow that is induced by hyperthermia, as this brain region is known to play a key role in renal function and may contribute to the central pathways underlying thermoregulatory responses. In anesthetized rats, blood pressure, heart rate, renal blood flow, and tail skin temperature were recorded in response to elevating body core temperature. In the control group, saline was microinjected bilaterally into the PVN; in the second group, muscimol (1 nmol in 100 nl per side) was microinjected to inhibit neuronal activity in the PVN; and in a third group, muscimol was microinjected outside the PVN. Compared with control, microinjection of muscimol into the PVN did not significantly affect the blood pressure or heart rate responses. However, the normal reflex reduction in renal blood flow observed in response to hyperthermia in the control group (∼70% from a resting level of 11.5 ml/min) was abolished by the microinjection of muscimol into the PVN (maximum reduction of 8% from a resting of 9.1 ml/min). This effect was specific to the PVN since microinjection of muscimol outside the PVN did not prevent the normal renal blood flow response. The data suggest that the PVN plays an essential role in the reflex decrease in renal blood flow elicited by hyperthermia.

The role of the mediodorsal thalamic nucleus in human olfaction

Neurocase ◽  
2011 ◽  
Vol 17 (2) ◽  
pp. 148-159 ◽  
Author(s):  
Wendy W. P. Tham ◽  
Richard J. Stevenson ◽  
Laurie A. Miller
Keyword(s):  
Thalamic Nucleus ◽  
Mediodorsal Thalamic Nucleus ◽  
Human Olfaction
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