To assess the influence of the total artificial heart replacement on autonomic nervous system, sympathetic neurogram was analyzed by power spectrum and coherence function. Two pneumatically driven sac-type ventricular assist devices were implanted as biventricular bypass (BVB) in adult mongrel dogs. After the BVB pumping, natural heart was electrically fibrillated to constitute the BVB type TAH model. Renal sympathetic nerve activity (RSNA) was recorded using the bipolar electrode attached to the left renal sympathetic nerve. RSNA was amplified and integrated by the use of R-C integrator. Power spectra of the RSNA and the values of squared coherence between the arterial pressure waveform and the RSNA were calculated by the computer system. In animal with TAH, coherence at the cardiac rhythm frequency was decreased, and coherence at the TAH pumping rhythm frequency was increased. These results indicate that the arterial pulse wave which was observed in TAH animal contributed to sympathetic neurogram.
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Zhongguo Yi Xue Ke Xue Yuan Xue Bao
October 2024
Department Five of Orthopedics and Traumatology, Changzhou Hospital of Traditional Chinese Medicine,Changzhou,Jiangsu 213000,China.
The joints have abundant sensory nerves and sympathetic nerve fibers,which convert physical and chemical stimuli in the joints into nerve impulses that are transmitted to the central nervous system and participate in the hypersensitivity reactions of inflammatory joint diseases such as osteoarthritis (OA).This paper summarizes the distribution and functional characteristics of intra-articular nerves and focuses on the mechanism of the vagus-sympathetic autonomic circuit in regulating the immune microenvironment in joints in the case of OA.In addition,intra-articular inflammatory cytokines represented by tumor necrosis factor-α and interleukin-6 directly or indirectly induce sensory nerve action potential and activate the pain transduction pathway from the local joint to the central nervous system.
View Article and Find Full Text PDFJ Neurophysiol
June 2024
Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada.
Microneurographic recordings of muscle sympathetic nerve activity (MSNA) reflect postganglionic sympathetic axonal activity directed toward the skeletal muscle vasculature. Recordings are typically evaluated for spontaneous bursts of MSNA; however, the filtering and integration of raw neurograms to obtain multiunit bursts conceals the underlying c-fiber discharge behavior. The continuous wavelet transform with matched mother wavelet has permitted the assessment of action potential discharge patterns, but this approach uses a mother wavelet optimized for an amplifier that is no longer commercially available (University of Iowa Bioengineering Nerve Traffic Analysis System; Iowa NTA).
View Article and Find Full Text PDFJ Neurophysiol
April 2023
Neurovascular Research Laboratory, Department of Kinesiology, University of Western Ontario, London, Ontario, Canada.
This study tested the hypothesis that during fatiguing volitional exercise in humans, descending cortical signals and ascending skeletal muscle metaboreflex signals exert divergent control over baroreflex resetting of sympathetic action potential (AP) discharge. We quantified the baroreflex gain for sympathetic AP clusters within the muscle sympathetic nerve activity neurogram (peroneal microneurography and continuous wavelet transform) during baseline (BSL), the first 2-min of a 5-min isometric handgrip (20% of maximal effort; IHG1), the last 2-min of IHG (IHG2), and during postexercise circulatory occlusion (PECO) in seven healthy participants. AP baroreflex threshold gain was measured as the slope of the linear relationship between AP probability (%) versus diastolic blood pressure (DBP; mmHg) for 10 normalized AP clusters.
View Article and Find Full Text PDFFront Neurosci
December 2021
Neuroscience Research Australia, Sydney, NSW, Australia.
We previously demonstrated that muscle sympathetic nerve activity (MSNA) increases to contracting muscle as well as to non-contracting muscle, but this was only assessed during isometric exercise at ∼10% of maximum voluntary contraction (MVC). Given that high-intensity isometric contractions will release more metabolites, we tested the hypothesis that the metaboreflex is expressed in the contracting muscle during high-intensity but not low-intensity exercise. MSNA was recorded continuously via a tungsten microelectrode inserted percutaneously into the right common peroneal nerve in 12 participants, performing isometric dorsiflexion of the right ankle at 10, 20, 30, 40, and 50% MVC for 2 min.
View Article and Find Full Text PDFJ Neurophysiol
November 2021
Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada.
Muscle sympathetic nerve activity (MSNA) can be acquired from humans using the technique of microneurography. The resulting integrated neurogram displays pulse-synchronous bursts of sympathetic activity, which undergoes processing for standard MSNA metrics including burst frequency, height, area, incidence, total activity, and latency. The procedure for detecting bursts of MSNA and calculating burst metrics is tedious and differs widely among laboratories worldwide.
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