Balance control mechanisms do not benefit from successive stimulation of different sensory systems

ABSTRACTIn humans, to reduce deviations from a perfect upright position, information from various sensory cues is combined and continuously weighted based on its reliability. Combining noisy sensory information to produce a coherent and accurate estimate of body sway is a central problem in human balance control. In this study, we first compared the ability of the sensorimotor control mechanisms to deal with altered ankle proprioception or vestibular information (i.e., the single sensory condition). Then, we evaluated whether successive stimulation of difference sensory systems (e.g., Achilles tendon vibration followed by electrical vestibular stimulation, or vice versa) produced a greater alteration of balance control (i.e., the mix sensory condition). Electrical vestibular stimulation (head turned ∼90°) and Achilles tendon vibration induced backward body sways. We calculated the root mean square value of the scalar distance between the center of pressure and the center of gravity as well as the time needed to regain balance (i.e., stabilization time). Furthermore, the peak ground reaction force along the anteroposterior axis, immediately following stimulation offset, was determined to compare the balance destabilization across the different conditions. In single conditions, during vestibular or Achilles tendon vibration, no difference in balance control was observed. When sensory information returned to normal, balance control was worse following Achilles tendon vibration. Compared to that of the single sensory condition, successive stimulation of different sensory systems (i.e., mix conditions) increased stabilization time. Overall, the present results reveal that single and successive sensory stimulation challenges the sensorimotor control mechanisms differently.

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Angiotensin-Converting Enzyme 2 (ACE2) as a Potential Diagnostic and Prognostic Biomarker for Chronic Inflammatory Lung Diseases

Genes ◽

10.3390/genes12071054 ◽

2021 ◽

Vol 12 (7) ◽

pp. 1054

Author(s):

Dejan Marčetić ◽

Miroslav Samaržija ◽

Andrea Vukić Dugac ◽

Jelena Knežević

Keyword(s):

Angiotensin Converting Enzyme ◽

Lung Diseases ◽

Balance Control ◽

Chronic Obstructive ◽

Electrolyte Balance ◽

Control Mechanisms ◽

Pathophysiological Mechanism ◽

Converting Enzyme ◽

Angiotensin Converting Enzyme 2 ◽

Potential Biomarker

Chronic inflammatory lung diseases are characterized by uncontrolled immune response in the airways as their main pathophysiological manifestation. The lack of specific diagnostic and therapeutic biomarkers for many pulmonary diseases represents a major challenge for pulmonologists. The majority of the currently approved therapeutic approaches are focused on achieving disease remission, although there is no guarantee of complete recovery. It is known that angiotensin-converting enzyme 2 (ACE2), an important counter-regulatory component of the renin–angiotensin–aldosterone system (RAAS), is expressed in the airways. It has been shown that ACE2 plays a role in systemic regulation of the cardiovascular and renal systems, lungs and liver by acting on blood pressure, electrolyte balance control mechanisms and inflammation. Its protective role in the lungs has also been presented, but the exact pathophysiological mechanism of action is still elusive. The aim of this study is to review and discuss recent findings about ACE2, including its potential role in the pathophysiology of chronic inflammatory lung diseases:, i.e., chronic obstructive pulmonary disease, asthma, and pulmonary hypertension. Additionally, in the light of the coronavirus 2019 disease (COVID-19), we will discuss the role of ACE2 in the pathophysiology of this disease, mainly represented by different grades of pulmonary problems. We believe that these insights will open up new perspectives for the future use of ACE2 as a potential biomarker for early diagnosis and monitoring of chronic inflammatory lung diseases.

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Stimulation of steroidogenesis in cultured rat adrenocortical cells by unsaturated fatty acids

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1995.268.6.r1484 ◽

1995 ◽

Vol 268 (6) ◽

pp. R1484-R1490 ◽

Cited By ~ 5

Author(s):

I. Sarel ◽

E. P. Widmaier

Keyword(s):

Fatty Acids ◽

Unsaturated Fatty Acids ◽

Lipid Homeostasis ◽

Control Mechanisms ◽

Adrenocortical Cells ◽

Stimulatory Action ◽

Apparent Lack ◽

Naturally Occurring ◽

Oleic And Linoleic Acids ◽

Stimulation Of

The hypothesis that the stimulatory action of free fatty acids (FFA) in the hypothalamic-pituitary-adrenocortical (HPA) axis occurs in part at the adrenal cortex was evaluated. Pathophysiological concentrations of oleic and linoleic acids, but not stearic or caprylic acid, stimulated steroidogenesis from cultured rat adrenocortical cells (concentrations eliciting 50% of maximal responses, approximately 60 and 120 microM, respectively), with a latency of 90 min. Maximal stimulation of steroidogenesis by both acids was < 50% of that produced by adrenocorticotropic hormone (ACTH) and was blocked by cycloheximide. The maximal steroidogenic response to ACTH was inhibited approximately 50% by oleic acid. The actions of oleic and linoleic acids were not associated with an increase in adenosine 3',5'-cyclic monophosphate (cAMP) secretion but appeared to require intracellular oxidation. None of the lipids influenced cell viability or corticosterone radioimmunoassay. The latency of the steroidogenic response, the putative requirement for intracellular oxidation, and the apparent lack of involvement of cAMP suggest a mechanism of action of FFA distinct from that of ACTH, yet still requiring protein synthesis. It is concluded that the modulation of steroidogenesis by these abundant naturally occurring lipids may be an important component of the control mechanisms within the HPA pathway in disorders of lipid homeostasis (e.g., obesity, starvation, or diabetes).

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Towards Using the Instrumented Timed Up-and-Go Test for Screening of Sensory System Performance for Balance Control in Older Adults

Sensors ◽

10.3390/s19030622 ◽

2019 ◽

Vol 19 (3) ◽

pp. 622 ◽

Cited By ~ 3

Author(s):

Thomas Gerhardy ◽

Katharina Gordt ◽

Carl-Philipp Jansen ◽

Michael Schwenk

Keyword(s):

Older Adults ◽

System Performance ◽

Fall Risk ◽

Balance Control ◽

Sensory System ◽

Sensory Systems ◽

Community Dwelling ◽

Functional Mobility ◽

Timed Up And Go ◽

Community Dwelling Older Adults

Background: Decreasing performance of the sensory systems’ for balance control, including the visual, somatosensory and vestibular system, is associated with increased fall risk in older adults. A smartphone-based version of the Timed Up-and-Go (mTUG) may allow screening sensory balance impairments through mTUG subphases. The association between mTUG subphases and sensory system performance is examined. Methods: Functional mobility of forty-one community-dwelling older adults (>55 years) was measured using a validated mTUG. Duration of mTUG and its subphases ‘sit-to-walk’, ‘walking’, ‘turning’, ‘turn-to-sit’ and ‘sit-down’ were extracted. Sensory systems’ performance was quantified by validated posturography during standing (30 s) under different conditions. Visual, somatosensory and vestibular control ratios (CR) were calculated from posturography and correlated with mTUG subphases. Results: Vestibular CR correlated with mTUG total time (r = 0.54; p < 0.01), subphases ‘walking’ (r = 0.56; p < 0.01), and ‘turning’ (r = 0.43; p = 0.01). Somatosensory CR correlated with mTUG total time (r = 0.52; p = 0.01), subphases ‘walking’ (r = 0.52; p < 0.01) and ‘turning’ (r = 0.44; p < 0.01). Conclusions: Supporting the proposed approach, results indicate an association between specific mTUG subphases and sensory system performance. mTUG subphases ‘walking’ and ‘turning’ may allow screening for sensory system deterioration. This is a first step towards an objective, detailed and expeditious balance control assessment, however needing validation in a larger study.

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Human Adrenal Cells in Culture Produce Both Ouabain-like and Dihydroouabain-like Factors

Clinical Chemistry ◽

10.1093/clinchem/48.10.1720 ◽

2002 ◽

Vol 48 (10) ◽

pp. 1720-1730 ◽

Cited By ~ 30

Author(s):

M Adnan El-Masri ◽

Barbara J Clark ◽

Hassan M Qazzaz ◽

Roland Valdes

Keyword(s):

Catalytic Activity ◽

Sodium Pump ◽

Reversed Phase ◽

Control Mechanisms ◽

Serum Free Medium ◽

Adrenocortical Cells ◽

Α Subunit ◽

Adrenal Cells ◽

Cells In Culture ◽

Stimulation Of

Abstract Background: Ouabain-like factor (OLF) and its newly discovered reduced species, dihydroouabain-like factor (Dh-OLF), are mammalian cardenolides whose structural and functional characteristics are similar to the plant-derived compounds ouabain and dihydroouabain. These endogenous compounds are believed to be produced by the adrenals and to constitute part of an hormonal axis that may regulate the catalytic activity of the α-subunit of Na+,K+-ATPase. We developed antibodies sufficiently specific to distinguish between OLF and Dh-OLF, and in this study demonstrate the selective secretion of OLF and Dh-OLF from human H295R-1 adrenocortical cells in culture. Methods: We used reversed-phase HPLC, inhibition of Na+,K+-ATPase catalytic activity, and two enzyme immunoassays developed with antibodies specific to ouabain and dihydroouabain to purify and characterize the secretion of these two compounds by human adrenal cells in culture. Purified antisera had high titers (1 × 106 for ouabain and 8 ×105 for dihydroouabain) and were specific to their corresponding antigens. Results: Human H295R-1 cells grown in serum-free medium secreted 0.18 ± 0.03 pmol of OLF and 0.39 ± 0.04 pmol of Dh-OLF per 106 cells in 24 h. Both OLF and Dh-OLF inhibited the ouabain-sensitive catalytic activity of the sodium pump (0.03 μmol/L OLF inhibited 29% of the catalytic activity; 0.07 μmol/L Dh-OLF inhibited 17%). Stimulation of the cell culture by dibutryl cAMP increased the secretion of Dh-OLF 50% over control (unstimulated), whereas the secretion of OLF did not increase significantly. Conclusions: OLF and Dh-OLF are secreted by human adrenal cells, and antibodies specific to these two compounds can be developed, using the plant-derived counterparts as antigens. The secretion of Dh-OLF is responsive to a cAMP-dependent stimulation mechanism, whereas OLF is not. Our data suggest that either the secretory or biosynthetic pathways for production of these two compounds by human adrenal cells may have different control mechanisms or that they may be linked via a precursor–product relationship.

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Modulating locomotor adaptation with cerebellar stimulation

Journal of Neurophysiology ◽

10.1152/jn.00645.2011 ◽

2012 ◽

Vol 107 (11) ◽

pp. 2950-2957 ◽

Cited By ~ 159

Author(s):

Gowri Jayaram ◽

Byron Tang ◽

Rani Pallegadda ◽

Erin V. L. Vasudevan ◽

Pablo Celnik ◽

...

Keyword(s):

Neural Circuits ◽

Critical Role ◽

Locomotor Training ◽

Control Mechanisms ◽

Adaptive Process ◽

Locomotor Adaptation ◽

Neurological Patients ◽

Cerebellar Tdcs ◽

Stimulation Of ◽

Cerebellar Stimulation

Human locomotor adaptation is necessary to maintain flexibility of walking. Several lines of research suggest that the cerebellum plays a critical role in motor adaptation. In this study we investigated the effects of noninvasive stimulation of the cerebellum to enhance locomotor adaptation. We found that anodal cerebellar transcranial direct current stimulation (tDCS) applied during adaptation expedited the adaptive process while cathodal cerebellar tDCS slowed it down, without affecting the rate of de-adaptation of the new locomotor pattern. Interestingly, cerebellar tDCS affected the adaptation rate of spatial but not temporal elements of walking. It may be that spatial and temporal control mechanisms are accessible through different neural circuits. Our results suggest that tDCS could be used as a tool to modulate locomotor training in neurological patients with gait impairments.

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Cholinergic control mechanisms for immunoreactive motilin release and motility in the canine duodenum

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y83-155 ◽

1983 ◽

Vol 61 (9) ◽

pp. 1042-1049 ◽

Cited By ~ 29

Author(s):

J. E. T. Fox ◽

E. E. Daniel ◽

J. Jury ◽

N. S. Track ◽

S. Chiu

Keyword(s):

Muscarinic Receptor ◽

Close Correlation ◽

Receptor Activation ◽

Vagal Activity ◽

Control Mechanisms ◽

Field Stimulation ◽

Neural Pathway ◽

Cholinergic Nerves ◽

Duodenal Motility ◽

Stimulation Of

The relationship of immunoreactive (IR) motilin release from the duodenum to duodenal motility changes was investigated in anaesthetized dogs. Stimulation of one or both vagi at 5 or 15 Hz or field stimulation of intrinsic duodenal nerves produced Significant increases in duodenal vein IR motilin concentrations and accompanying increases in duodenal motility. However, only stimulation of both vagi at 15 Hz produced significant changes in peripheral venous concentrations of IR motilin. These occurred after a delay at a time when both the duodenum and the antrum were quiescent. Either hexamelhonium or atropine blocked IR motilin release induced by stimulation of intrinsic or extrinsic nerves while only atropine inhibited the release induced by intraarterial carbachol. The response stimulated by carbachol and blocked by atropine was tetroclotoxin insensitive and the muscarinic receptor involved was presumably located on a nonneural structure. The site sensitive to hexamethonium was presumably the neural pathway which terminated at the muscarinic receptor. Concomitant studies of duodenal motility responses to vagal and field stimulation suggested a conventional neural pathway with preganglionic cholinergic nerves in the vagus, postganglionic cholinergic nerves in the duodenum (activated by field stimulation) and a smooth muscle muscarinic receptor. Activation of antral motility by stimulation of the abdominal vagus or intraarterial carbachol injections to the antrum increased duodenal IR motilin release in the absence of duodenal motility. Thus activation of the intrinsic nerves which cross the pylorus initiated IR motilin release as well as inhibited duodenal motility. Aside from this motility-independent release there was a close correlation between increased duodenal motility and IR motilin release. These findings imply that the rise in endogenous IR motilin levels associated with the passage of the activity front of the migrating motor complex through the duodenum may be initiated by the combined effects of increased vagal activity and increased gastric and duodenal motor activity.

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The Dorsomedial Hypothalamic Nucleus In Autonomic And Neuroendocrine Homeostasis

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques ◽

10.1017/s0317167100019971 ◽

1975 ◽

Vol 2 (1) ◽

pp. 45-60 ◽

Cited By ~ 44

Author(s):

Lee L. Bernardis

Keyword(s):

Growth Hormone ◽

Electrical Stimulation ◽

Food Intake ◽

Present Report ◽

Hypothalamic Nucleus ◽

Control Mechanisms ◽

Storage Site ◽

Dorsomedial Hypothalamic Nucleus ◽

Cervical Stimulation ◽

Stimulation Of

SUMMARY:Median eminence and ventromedial hypothalamus have in the past been the principal foci of research in neuroendocrine and neurovisceral control mechanisms. The present report provides an overview of work involving the dorsomedial hypothalamic nucleus (DMN). This structure is located dorsal to the ventromedial hypothalamic nucleus (VMN) and extends anteroposteriorly from the plane of the largest cross section of the VMN to the plane of the dorsal premammillary nucleus. Fibers from the DMN pass with the periventricular system and the dorsal longitudinal fasciculus of Schütz and have been traced to the midbrain tegmentum and reticular formation. Intrahypothalamic connections involve intensive networks between DMN, lateral hypothalamic nucleus (LHN) and VMN. Regarding neurotransmitters, recent studies indicate that the DMN receives noradrenergic innervation along two pathways, a dorsal and a ventral one. Monoamine-containing systems approach the DMN from the lateral hypothalamus and the bulk of these fibers are carried in the medium forebrain bundle from their cells of origin in the brain stem. Studies of the vascular supply indicate that both VMN and DMN receive their blood supply from the internal carotid artery. It has been recently demonstrated that the DMN is involved in the control of food intake and possibly water intake as well. Discrete lesions in the DMN have caused hypophagia and hypodipsia, and implantation of epinephrine and norepinephrine in this area has initiated eating. Many years ago, electrical stimulation of this area was reported to cause eating. Although DMN lesions cause hypodipsia, they do not result in the reduced water/food intake ratios that are so characteristic of the VMN syndrome. DMN lesions are also followed by reduced spontaneous activity (running wheel), but this reduced activity is not accompanied by increased weight gain and accretion of adipose tissue, the latter being consistently observed in the VMN rat. Rather, carcass fat remains normal in the DMN rat and carcass protein is either normal or slightly increased. Many of the aforementioned changes in weanling rats with DMN lesions, however, are not matched by similar alterations in the intermediary metabolism of carbohydrate and lipid. Possibly this is due to a “resetting” of a central autonomic control system that makes it possible for the DMN rat to adapt more efficiently to a reduced influx of substrate, i.e. the consistent hypophagia. From a review of the literature it appears that the DMN and their circuitry are involved in only a few neuroendocrine, i.e. hypothalamohypophyseal control mechanisms. Both lesion and cervical stimulation experiments suggest an involvement of the DMN in the control of LTH. Circumstantial evidence points to the DMN as a possible formation and/or storage site of growth hormone inhibiting factor (GIF). Although DMN rats show reduced ponderal and linear growth, they have been found to have normal or elevated plasma growth hormone (GH) levels. Both lesion and stimulation studies have yielded the impression that the DMN is not involved in thyroid, i.e., thyrotropin stimulating hormone releasing factor (TSHRF) control. Electrical stimulation of the DMN has been reported to result in a positive correlation between adrenal blood flow and adrenal corticoid release in hypophysectomized dogs. This has been interpreted as a coordinated response at the level of a “dorsomedial sympathetic vasodilator relay” rather than a “true” neuroendocrine effect via corticotropin releasing factor (CRF). Experiments that failed to demonstrate a relationship between the DMN and the tonic and cyclic control of luteinizing hormone releasing factor (LHRF) are discussed. The data reviewed indicate the existence in the dorsomedial hypothalamus of an area that exerts a profound influence on many aspects of neurovisceral and some neuroendocrine control systems.

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Odor-evoked Increases in Spiking Variability in the Olfactory Bulb

10.1101/2021.03.05.434131 ◽

2021 ◽

Author(s):

Cheng Ly ◽

Andrea K. Barreiro ◽

Shree Hari Gautam ◽

Woodrow L. Shew

Keyword(s):

Olfactory Bulb ◽

General Principle ◽

Sensory Stimulation ◽

Sensory Systems ◽

Stimulus Onset ◽

Viable Alternative ◽

Optogenetic Stimulation ◽

Potential Benefits ◽

Coding Strategy ◽

Stimulation Of

AbstractAt the onset of sensory stimulation, the variability and co-variability of spiking activity is widely reported to decrease, especially in cortex. Considering the potential benefits of such decreased variability for coding, it has been suggested that this could be a general principle governing all sensory systems. Here we show that this is not so. We recorded neurons in olfactory bulb (OB) of anesthetized rats and found increased variability and co-variability of spiking at the onset of olfactory stimulation. Using models and analysis, we predicted that these increases arise due to network interactions within OB, without increasing variability of input from the nose. We tested and confirmed this prediction using optogenetic stimulation of OB in awake animals. Our results establish increases in spiking variability at stimulus onset as a viable alternative coding strategy to the more commonly observed decreases in variability in many cortical systems.

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Sensory control mechanisms of the uropod equilibrium reflex during walking in the crayfish Procambarus clarkii

Journal of Experimental Biology ◽

10.1242/jeb.199.3.521 ◽

1996 ◽

Vol 199 (3) ◽

pp. 521-528 ◽

Cited By ~ 1

Author(s):

M Murayama ◽

M Takahata

Keyword(s):

Transient Response ◽

Motor System ◽

Procambarus Clarkii ◽

Upright Position ◽

Control Mechanisms ◽

Animal Body ◽

Prolonged Stimulation ◽

Transient Control ◽

Body Rolling ◽

Stimulation Of

The temporal characteristics of statocyst and leg proprioceptive inputs to the uropod motor system were investigated in crayfish using behavioural and electromyographic analyses to elucidate their functional roles in the control of the uropod steering response under natural conditions. When the animal, which was suspended in the air without a footboard, was actively extending its abdomen, prolonged stimulation of the statocysts by body rolling elicited a maintained asymmetrical configuration of the bilateral uropods. Prolonged stimulation of the walking legs by footboard tilting with the animal body held in the upright position elicited a transient uropod response. When the treadmill was tilted while the animal was walking on it in the upright position, the uropods showed the same transient response. However, when the animal body was rolled, together with the treadmill, while the animal was walking on it, the uropods showed a transient response which was reversed in direction compared with that observed during body rolling without a footboard. This transient response was abolished by the removal of the statoliths. The results show that the statocysts and leg proprioceptors exert sustained and transient control effects, respectively, on the uropod motor system during walking. It is also suggested that the uropod response to body rolling during walking is controlled primarily by leg proprioceptor signals which result from statocyst-induced changes in the leg position.

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