Ivan Poliacek - Academia.edu (original) (raw)
Papers by Ivan Poliacek
The FASEB Journal, Apr 1, 2011
Respiratory Physiology & Neurobiology, Sep 1, 2023
The FASEB Journal, Apr 1, 2018
Respiratory Physiology & Neurobiology, 2023
Physiological Research, Mar 26, 2020
The FASEB Journal, Apr 1, 2015
Repetitive cough induces profound hyperventilation with no loss of motor drive to the respiratory... more Repetitive cough induces profound hyperventilation with no loss of motor drive to the respiratory muscles. However, this hyperventilation routinely results in PC02 values of 7.5. This cough-induced derangement presents a challenge for the respiratory control system especially during the cough-eupnea transition. We hypothesized that during this transition: a) there would be limited apnea, and b) the eupneic cycles would be significantly affected by the previous level of hyperventilation. Repetitive cough was elicited by mechanical stimulation of the intra-thoracic trachea in anesthetized, spontaneously breathing cats (N = 6). Electromyograms were recorded from the diaphragm, parasternal, and internal oblique. During repetitive coughing, C02 levels dropped from a mean of 33.05 + 2.16 mmHg to 11.67 + 3.61 mmHg. The cough-to-eupnea transition was marked by hypopnea durations of 17.59 + 7.7 s. CO2 levels during cough trials had a small negative correlation with cough-to-eupnoea ...
Acta Medica Martiniana
The impact of D,L – homocysteic acid (DLH) microinjection (non-specific glutamate receptor agonis... more The impact of D,L – homocysteic acid (DLH) microinjection (non-specific glutamate receptor agonist that causes excitation of neurons) into the Bötzinger complex area (BOT) was simulated using computer model of quiet breathing and cough reflex. Integrated signals from simulated neuronal populations innervating inspiratory phrenic and expiratory lumbar motoneurons were obtained. We analysed durations and amplitudes of these “pre-phrenic and pre-lumbar” activities during quiet breathing and cough reflex and the number of coughs elicited by a fictive 10-second-long stimulation. Model fibre population provides virtual DLH related excitation to expiratory neuronal populations with augmenting discharge pattern (BOT neurons). The excitation was modelled by a higher number of fibres and terminals (simulated a higher number of excitatory inputs) or by a higher synaptic strength (simulated a higher effect of excitatory inputs). Our simulations have demonstrated a high analogy of cough and brea...
Respiratory Physiology & Neurobiology, 2021
One of the great dilemmas of our time is how we will secure and provide plentiful, healthy and nu... more One of the great dilemmas of our time is how we will secure and provide plentiful, healthy and nutritious food for all, do so in an environmentally sustainable and safe manner, while addressing the multiple burdens of undernutrition, overweight and obesity and micronutrient deficiencies. The food security directive focuses predominantly on ensuring the world is producing and consuming enough calories in bulk to reduce hunger and safeguard survival, as opposed to a goal that includes nutrition for well-being and development. To advance the dialogue, it is necessary to consider the ethical questions that swirl around integrating nutrition into the food security paradigm. The health, environmental, economic, and societal costs will be substantial if we do not change our course of action when it comes to feeding the world. Yet solving this problem is riddled with ethical and moral implications. Key ethical issues to consider include how to make societal decisions and define values about food security that impact nutrition outcomes, and the ethical trade-offs between environmental sustainability and ensuring that individual dietary and nutritional needs are met. Such complex issues underscore the need to articulate the broader ethical landscape of the nutrition debate within global food security.
European Respiratory Journal, 2012
Cough, the most important airways defensive mechanism is modulated by many afferent inputs either... more Cough, the most important airways defensive mechanism is modulated by many afferent inputs either from respiratory tussigenic areas, but also by afferent drive from other organs. Modulation of cough by nasal afferent inputs could either facilitate cough response or inhibit it in animal models, depending on the type of trigeminal afferents which are stimulated. In recent study we addressed the question of possible bidirectional modulation of cough response in human healthy volunteers by nasal challenges with TRPA1 and TRPM8 agonists respectively. After nasal challenges with AITC, cinnamaldehe, (-) menthol and (+) menthol (all 10-3 M, nasal symptom score, cough threshold (C2), urge to cough (Cu) and cumulative cough response had been tested). Nasal challenges of TRPA1 relevant agonists induced considerable nasal symptoms, significantly enhanced urge to cough (p Except the role of trigeminal afferents expressing TRP channels, also olfactory nerve endings, trigemino – olfactoric relatio...
Physiological Research, 2020
We studied the effects of GABA receptor agonists microinjections in medullary raphé on the mechan... more We studied the effects of GABA receptor agonists microinjections in medullary raphé on the mechanically induced tracheobronchial cough response in anesthetized, unparalyzed, spontaneously breathing cats. The results suggest that GABA-ergic inhibition significantly contributes to the regulation of cough reflex by action of both GABAA and GABAB receptors. The data are consistent with inhomogeneous occurrence of GABA-ergic neurons in medullary raphé and their different involvement in the cough reflex control. Cells within rostral nucleus raphé obscurus with dominant role of GABAA receptors and neurons of rostral nucleus raphé pallidus and caudal nucleus raphé magnus with dominant role of GABAB receptors participate in regulation of cough expiratory efforts. These cough control elements are distinct from cough gating mechanism. GABA-ergic inhibition in the raphé caudal to obex had insignificant effect on cough. Contradictory findings for GABA, muscimol and baclofen administration in med...
Respiratory Physiology & Neurobiology, 2018
Highlights Of the manuscript I Poliacek et al. The central pattern of tracheobronchial cough is a... more Highlights Of the manuscript I Poliacek et al. The central pattern of tracheobronchial cough is affected by inspiratory resistance and expiratory occlusionthe evidence for volume feedback during cough expiration. are as follows:-evidence for volume feedback functioning during cough expiratory phase, with possible relevance to cough impairment-significant alteration in the cough motor pattern induced by experimental cough expiratory occlusion-surprising effect of cough expiratory occlusion on cough number and cough inspiratory component ABSTRACT The role of pulmonary stretch receptor discharge and volume feedback in modulation of tracheobronchial cough is not fully understood. The current study investigates the effect of expiratory occlusion with or without preceding inspiratory resistance (delivery of tidal or cough volume by the ventilator lasting over the active cough expiratory period) on the cough motor
Acta Medica Martiniana, 2016
Upper airways (UA) are an organic component of the respiratory tract, they serve to respiration, ... more Upper airways (UA) are an organic component of the respiratory tract, they serve to respiration, respiratory tract protection and defense, phonation, deglutition, etc. The functions of UA are regulated by motor control of the oral, pharyngeal, and laryngeal muscles.UA typically stiffen and widen during inspiration mainly due to the activation of the alae nasi, genioglossus m., pharyngeal dilators, and laryngeal abductors. These and other UA muscles (e.g. laryngeal and pharyngeal constrictors) may express varoius activity patterns, actively shaping UA depending on species, arousal, respiratory drive, and behavior being executed. E.g. during coughing and sneezing laryngeal movement consists of abductions in inspiration and expiration and adductions in compression and subsequent constriction phase. The cricopharyngeus m., in cough expiration the superior pharyngeal constrictor and in the sneeze expiration the styloglossus and levator veli palatini m. are activated. Unlike in breathing ...
Respiratory Physiology & Neurobiology, 2018
GABA, muscimol, and baclofen were microinjected into the rostral (rNTS) and caudal solitary tract... more GABA, muscimol, and baclofen were microinjected into the rostral (rNTS) and caudal solitary tract nucleus (cNTS) in 24 anesthetized cats. Electromyograms (EMGs) of diaphragm (DIA) and abdominal muscles (ABD), blood pressure and esophageal pressure (EP) were recorded and analysed. Bilateral microinjections of 1 mM GABA (total 66 ± 4 nl), 1 mM baclofen (64 ± 4 nl) and unilateral microinjections of 0.5 mM muscimol (33 ± 1 nl) in the rNTS significantly reduced cough number (CN), amplitudes of ABD EMGs, expiratory EP, and prolonged the duration of the cough inspiratory phase. GABA microinjections decreased the amplitudes of cough-related DIA EMGs and inspiratory EP; muscimol microinjections decreased the cough DIA EMG on the contralateral side. Only microinjections of GABA into the cNTS suppressed CN. In some cases, microinjections prolonged the inspiratory phase, lowered respiratory rate, changed the depth of breathing, and increased blood pressure and heart rate. Our results confirm that GABA-ergic inhibitory mechanisms in the rNTS can regulate coughing in the anesthetized cat.
Acta Veterinaria Brno, 2005
The power spectral analysis of the phrenic nerve activity during eupnoeic inspiration and during ... more The power spectral analysis of the phrenic nerve activity during eupnoeic inspiration and during inspiratory phase of mechanically induced tracheobronchial and laryngeal cough was performed on cats anaesthetized by chloralose or pentobarbital. Distribution of the spectral power was analysed in the four frequency bands: p0-20, p20-40, p40-60, p60-80, which represent frequency range of the corresponding percentage intervals of total spectral power. The computed spectra were compared. The total power of cough inspiratory activity was several times higher, comparing to inspiration during quiet breathing. Cough spectra revealed the higher power at lower frequency range, being demonstrated as a narrower p0-20, comparing to the quiet breathing. No significant differences were determined in spectral power distribution between tracheobronchial and laryngeal coughs. The effect of anesthesia was manifested by narrower power interval p0-20 for eupnoeic inspiration and p40-60 for both types of cough (inspiratory phase) in cats under chloralose anesthesia, compared to those under pentobarbital anesthesia. Our findings indicate the significant differences in power spectra of phrenic nerve activity during eupnoea and cough.
Pulmonary Pharmacology & Therapeutics, Jun 1, 2011
Advances in experimental medicine and biology, 2013
The effects of microinjections of the excitatory neurotoxin kainic acid (2 mg/ml; 49 ± 1 nl) on t... more The effects of microinjections of the excitatory neurotoxin kainic acid (2 mg/ml; 49 ± 1 nl) on the mechanically induced tracheobronchial cough, sneeze, and solitary expulsions from the trachea were examined in 11 anesthetized rabbits. Kainic acid was injected into the medulla (1.6-2.8 mm rostral to the obex, 1.4-1.6 and 2.9-3.2 mm below the dorsal medullary surface). Blood pressure, esophageal pressure (EP), and electromyograms (EMGs) of the diaphragm (DIA) and abdominal muscles (ABD) were recorded. Kainic acid reduced the number of coughs (means ± SE) from 3.8 ± 2.0 to 0.9 ± 0.7 (p = 0.016), the amplitude of DIA cough from 90 ± 11 to 42 ± 13 % (p = 0.004), ABD EMG moving average from 103 ± 9 to 37 ± 15 % (p = 0.006), and inspiratory from 0.67 ± 0.13 to 0.36 ± 0.12 kPa (p = 0.013) and expiratory EP from 1.70 ± 0.54 to 0.89 ± 0.46 kPa (p = 0.008). Kainic acid had no effect on the number of sneeze reflexes nor did it affect solitary expulsions from the trachea. These effects were acc...
The FASEB Journal, Apr 1, 2011
Respiratory Physiology & Neurobiology, Sep 1, 2023
The FASEB Journal, Apr 1, 2018
Respiratory Physiology & Neurobiology, 2023
Physiological Research, Mar 26, 2020
The FASEB Journal, Apr 1, 2015
Repetitive cough induces profound hyperventilation with no loss of motor drive to the respiratory... more Repetitive cough induces profound hyperventilation with no loss of motor drive to the respiratory muscles. However, this hyperventilation routinely results in PC02 values of 7.5. This cough-induced derangement presents a challenge for the respiratory control system especially during the cough-eupnea transition. We hypothesized that during this transition: a) there would be limited apnea, and b) the eupneic cycles would be significantly affected by the previous level of hyperventilation. Repetitive cough was elicited by mechanical stimulation of the intra-thoracic trachea in anesthetized, spontaneously breathing cats (N = 6). Electromyograms were recorded from the diaphragm, parasternal, and internal oblique. During repetitive coughing, C02 levels dropped from a mean of 33.05 + 2.16 mmHg to 11.67 + 3.61 mmHg. The cough-to-eupnea transition was marked by hypopnea durations of 17.59 + 7.7 s. CO2 levels during cough trials had a small negative correlation with cough-to-eupnoea ...
Acta Medica Martiniana
The impact of D,L – homocysteic acid (DLH) microinjection (non-specific glutamate receptor agonis... more The impact of D,L – homocysteic acid (DLH) microinjection (non-specific glutamate receptor agonist that causes excitation of neurons) into the Bötzinger complex area (BOT) was simulated using computer model of quiet breathing and cough reflex. Integrated signals from simulated neuronal populations innervating inspiratory phrenic and expiratory lumbar motoneurons were obtained. We analysed durations and amplitudes of these “pre-phrenic and pre-lumbar” activities during quiet breathing and cough reflex and the number of coughs elicited by a fictive 10-second-long stimulation. Model fibre population provides virtual DLH related excitation to expiratory neuronal populations with augmenting discharge pattern (BOT neurons). The excitation was modelled by a higher number of fibres and terminals (simulated a higher number of excitatory inputs) or by a higher synaptic strength (simulated a higher effect of excitatory inputs). Our simulations have demonstrated a high analogy of cough and brea...
Respiratory Physiology & Neurobiology, 2021
One of the great dilemmas of our time is how we will secure and provide plentiful, healthy and nu... more One of the great dilemmas of our time is how we will secure and provide plentiful, healthy and nutritious food for all, do so in an environmentally sustainable and safe manner, while addressing the multiple burdens of undernutrition, overweight and obesity and micronutrient deficiencies. The food security directive focuses predominantly on ensuring the world is producing and consuming enough calories in bulk to reduce hunger and safeguard survival, as opposed to a goal that includes nutrition for well-being and development. To advance the dialogue, it is necessary to consider the ethical questions that swirl around integrating nutrition into the food security paradigm. The health, environmental, economic, and societal costs will be substantial if we do not change our course of action when it comes to feeding the world. Yet solving this problem is riddled with ethical and moral implications. Key ethical issues to consider include how to make societal decisions and define values about food security that impact nutrition outcomes, and the ethical trade-offs between environmental sustainability and ensuring that individual dietary and nutritional needs are met. Such complex issues underscore the need to articulate the broader ethical landscape of the nutrition debate within global food security.
European Respiratory Journal, 2012
Cough, the most important airways defensive mechanism is modulated by many afferent inputs either... more Cough, the most important airways defensive mechanism is modulated by many afferent inputs either from respiratory tussigenic areas, but also by afferent drive from other organs. Modulation of cough by nasal afferent inputs could either facilitate cough response or inhibit it in animal models, depending on the type of trigeminal afferents which are stimulated. In recent study we addressed the question of possible bidirectional modulation of cough response in human healthy volunteers by nasal challenges with TRPA1 and TRPM8 agonists respectively. After nasal challenges with AITC, cinnamaldehe, (-) menthol and (+) menthol (all 10-3 M, nasal symptom score, cough threshold (C2), urge to cough (Cu) and cumulative cough response had been tested). Nasal challenges of TRPA1 relevant agonists induced considerable nasal symptoms, significantly enhanced urge to cough (p Except the role of trigeminal afferents expressing TRP channels, also olfactory nerve endings, trigemino – olfactoric relatio...
Physiological Research, 2020
We studied the effects of GABA receptor agonists microinjections in medullary raphé on the mechan... more We studied the effects of GABA receptor agonists microinjections in medullary raphé on the mechanically induced tracheobronchial cough response in anesthetized, unparalyzed, spontaneously breathing cats. The results suggest that GABA-ergic inhibition significantly contributes to the regulation of cough reflex by action of both GABAA and GABAB receptors. The data are consistent with inhomogeneous occurrence of GABA-ergic neurons in medullary raphé and their different involvement in the cough reflex control. Cells within rostral nucleus raphé obscurus with dominant role of GABAA receptors and neurons of rostral nucleus raphé pallidus and caudal nucleus raphé magnus with dominant role of GABAB receptors participate in regulation of cough expiratory efforts. These cough control elements are distinct from cough gating mechanism. GABA-ergic inhibition in the raphé caudal to obex had insignificant effect on cough. Contradictory findings for GABA, muscimol and baclofen administration in med...
Respiratory Physiology & Neurobiology, 2018
Highlights Of the manuscript I Poliacek et al. The central pattern of tracheobronchial cough is a... more Highlights Of the manuscript I Poliacek et al. The central pattern of tracheobronchial cough is affected by inspiratory resistance and expiratory occlusionthe evidence for volume feedback during cough expiration. are as follows:-evidence for volume feedback functioning during cough expiratory phase, with possible relevance to cough impairment-significant alteration in the cough motor pattern induced by experimental cough expiratory occlusion-surprising effect of cough expiratory occlusion on cough number and cough inspiratory component ABSTRACT The role of pulmonary stretch receptor discharge and volume feedback in modulation of tracheobronchial cough is not fully understood. The current study investigates the effect of expiratory occlusion with or without preceding inspiratory resistance (delivery of tidal or cough volume by the ventilator lasting over the active cough expiratory period) on the cough motor
Acta Medica Martiniana, 2016
Upper airways (UA) are an organic component of the respiratory tract, they serve to respiration, ... more Upper airways (UA) are an organic component of the respiratory tract, they serve to respiration, respiratory tract protection and defense, phonation, deglutition, etc. The functions of UA are regulated by motor control of the oral, pharyngeal, and laryngeal muscles.UA typically stiffen and widen during inspiration mainly due to the activation of the alae nasi, genioglossus m., pharyngeal dilators, and laryngeal abductors. These and other UA muscles (e.g. laryngeal and pharyngeal constrictors) may express varoius activity patterns, actively shaping UA depending on species, arousal, respiratory drive, and behavior being executed. E.g. during coughing and sneezing laryngeal movement consists of abductions in inspiration and expiration and adductions in compression and subsequent constriction phase. The cricopharyngeus m., in cough expiration the superior pharyngeal constrictor and in the sneeze expiration the styloglossus and levator veli palatini m. are activated. Unlike in breathing ...
Respiratory Physiology & Neurobiology, 2018
GABA, muscimol, and baclofen were microinjected into the rostral (rNTS) and caudal solitary tract... more GABA, muscimol, and baclofen were microinjected into the rostral (rNTS) and caudal solitary tract nucleus (cNTS) in 24 anesthetized cats. Electromyograms (EMGs) of diaphragm (DIA) and abdominal muscles (ABD), blood pressure and esophageal pressure (EP) were recorded and analysed. Bilateral microinjections of 1 mM GABA (total 66 ± 4 nl), 1 mM baclofen (64 ± 4 nl) and unilateral microinjections of 0.5 mM muscimol (33 ± 1 nl) in the rNTS significantly reduced cough number (CN), amplitudes of ABD EMGs, expiratory EP, and prolonged the duration of the cough inspiratory phase. GABA microinjections decreased the amplitudes of cough-related DIA EMGs and inspiratory EP; muscimol microinjections decreased the cough DIA EMG on the contralateral side. Only microinjections of GABA into the cNTS suppressed CN. In some cases, microinjections prolonged the inspiratory phase, lowered respiratory rate, changed the depth of breathing, and increased blood pressure and heart rate. Our results confirm that GABA-ergic inhibitory mechanisms in the rNTS can regulate coughing in the anesthetized cat.
Acta Veterinaria Brno, 2005
The power spectral analysis of the phrenic nerve activity during eupnoeic inspiration and during ... more The power spectral analysis of the phrenic nerve activity during eupnoeic inspiration and during inspiratory phase of mechanically induced tracheobronchial and laryngeal cough was performed on cats anaesthetized by chloralose or pentobarbital. Distribution of the spectral power was analysed in the four frequency bands: p0-20, p20-40, p40-60, p60-80, which represent frequency range of the corresponding percentage intervals of total spectral power. The computed spectra were compared. The total power of cough inspiratory activity was several times higher, comparing to inspiration during quiet breathing. Cough spectra revealed the higher power at lower frequency range, being demonstrated as a narrower p0-20, comparing to the quiet breathing. No significant differences were determined in spectral power distribution between tracheobronchial and laryngeal coughs. The effect of anesthesia was manifested by narrower power interval p0-20 for eupnoeic inspiration and p40-60 for both types of cough (inspiratory phase) in cats under chloralose anesthesia, compared to those under pentobarbital anesthesia. Our findings indicate the significant differences in power spectra of phrenic nerve activity during eupnoea and cough.
Pulmonary Pharmacology & Therapeutics, Jun 1, 2011
Advances in experimental medicine and biology, 2013
The effects of microinjections of the excitatory neurotoxin kainic acid (2 mg/ml; 49 ± 1 nl) on t... more The effects of microinjections of the excitatory neurotoxin kainic acid (2 mg/ml; 49 ± 1 nl) on the mechanically induced tracheobronchial cough, sneeze, and solitary expulsions from the trachea were examined in 11 anesthetized rabbits. Kainic acid was injected into the medulla (1.6-2.8 mm rostral to the obex, 1.4-1.6 and 2.9-3.2 mm below the dorsal medullary surface). Blood pressure, esophageal pressure (EP), and electromyograms (EMGs) of the diaphragm (DIA) and abdominal muscles (ABD) were recorded. Kainic acid reduced the number of coughs (means ± SE) from 3.8 ± 2.0 to 0.9 ± 0.7 (p = 0.016), the amplitude of DIA cough from 90 ± 11 to 42 ± 13 % (p = 0.004), ABD EMG moving average from 103 ± 9 to 37 ± 15 % (p = 0.006), and inspiratory from 0.67 ± 0.13 to 0.36 ± 0.12 kPa (p = 0.013) and expiratory EP from 1.70 ± 0.54 to 0.89 ± 0.46 kPa (p = 0.008). Kainic acid had no effect on the number of sneeze reflexes nor did it affect solitary expulsions from the trachea. These effects were acc...