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American Journal of Physiology.... May 2019Recent findings have shown that muscle contraction evokes an exaggerated pressor response in type 1 diabetes mellitus (T1DM) rats; however, it is not known whether the...
Recent findings have shown that muscle contraction evokes an exaggerated pressor response in type 1 diabetes mellitus (T1DM) rats; however, it is not known whether the mechanoreflex, which is commonly stimulated by stretching the Achilles tendon, contributes to this abnormal response. Furthermore, the role of mechano-gated Piezo channels, found on thin-fiber afferent endings, in evoking the mechanoreflex in T1DM is also unknown. Therefore, in male and female streptozotocin (STZ, 50 mg/kg)-induced T1DM and healthy control (CTL) rats, we examined the pressor and cardioaccelerator responses to tendon stretch during the early stage of the disease. To determine the role of Piezo channels, GsMTx-4, a selective Piezo channel inhibitor, was injected into the arterial supply of the hindlimb. At 1 wk after STZ injection in anesthetized, decerebrate rats, we stretched the Achilles tendon for 30 s and measured pressor and cardioaccelerator responses. We then compared pressor and cardioaccelerator responses to tendon stretch before and after GsMTx-4 injection (10 µg/100 ml). We found that the pressor (change in mean arterial pressure) response [41 ± 5 mmHg ( = 15) for STZ and 18 ± 3 mmHg ( = 11) for CTL ( < 0.01)] and cardioaccelerator (change in heart rate) response [18 ± 4 beats/min for STZ ( = 15) and 8 ± 2 beats/min ( = 11) for CTL ( < 0.05)] to tendon stretch were exaggerated in STZ rats. Local injection of GsMTx-4 attenuated the pressor [55 ± 7 mmHg ( = 6) before and 27 ± 9 mmHg ( = 6) after GsMTx-4 ( < 0.01)], but not the cardioaccelerator, response to tendon stretch in STZ rats and had no effect on either response in CTL rats. These data suggest that T1DM exaggerates the mechanoreflex response to tendon stretch and that Piezo channels play a role in this exaggeration.
Topics: Animals; Blood Pressure; Decerebrate State; Diabetes Mellitus, Experimental; Female; Hindlimb; Intercellular Signaling Peptides and Proteins; Male; Muscle Contraction; Muscle, Skeletal; Physical Conditioning, Animal; Rats, Sprague-Dawley; Reflex; Spider Venoms
PubMed: 30840487
DOI: 10.1152/ajpregu.00294.2018 -
Journal of Neurophysiology Jul 1964
Topics: Body Temperature Regulation; Brain; Decerebrate State; Locomotion; Mesencephalon; Rats; Research; Touch
PubMed: 14194963
DOI: 10.1152/jn.1964.27.4.635 -
Croatian Medical Journal Dec 1998To test if anesthetic procedures change the hemodynamic pattern in animals with experimental septic shock. (Comparative Study)
Comparative Study
AIM
To test if anesthetic procedures change the hemodynamic pattern in animals with experimental septic shock.
METHODS
The effect of two anesthetics on systemic hemodynamic and skeletal muscle microcirculatory responses in high cardiac output live E. coli bacteremia was studied in rats and compared to the effect of two other anesthetic procedures in previously published studies.
RESULTS
Baseline blood pressures and cardiac outputs were similar in rats with decerebrate, ketamine/xylazine, pentobarbital or urethane/chloralose anesthesia. There was a relative baseline tachycardia in decerebrate rats. Ketamine/xylazine anesthetized rats had reduced blood pressure, cardiac output, and heart rate. In decerebrate, pentobarbital, and urethane/chloralose anesthesia, cardiac output increased initially during bacteremia but did not remain elevated in pentobarbital anesthesia. Blood pressure and heart rate remained constant in pentobarbital, decerebrate, and urethane/chloralose anesth esia. During bacteremia, cardiac output, blood pressure, and vascular resistance did not change with ketamine/xylazine, but the heart rate increased. Baseline diameters of cremaster muscle large (A1) arterioles were higher in decerebrate anesthesia. A1 arterioles constricted during high cardiac output bacteremia in decerebrate rats, and pentobarbital or urethane/chloralose-anesthetized rats. A4 arterioles in bacteremia dilated in decerebrate and pentobarbital anesthesia, but did not change under urethane/chloralose and ketamine/xylazine anesthesia.
CONCLUSION
Anesthetics influence baseline systemic variables and the response of systemic hemodynamics of rats to E. coli bacteremia. During bacteremia, anesthetics primarily affect the reactivity of skeletal muscle small arterioles. Ketamine/xylazine anesthesia has the most pronounced effect on systemic and microcirculatory variables and seems to be an inappropriate choice in sepsis experiments in rats.
Topics: Anesthetics; Animals; Bacteremia; Chloralose; Decerebrate State; Disease Models, Animal; Escherichia coli Infections; Hemodynamics; Ketamine; Male; Microcirculation; Muscle, Skeletal; Pentobarbital; Rats; Rats, Sprague-Dawley; Reference Values; Shock, Septic; Urethane; Xylazine
PubMed: 9841938
DOI: No ID Found -
BMJ Case Reports Nov 2015The control of body posture is a complex activity that needs a very close relationship between different structures, such as the vestibular system, and the muscle and... (Review)
Review
The control of body posture is a complex activity that needs a very close relationship between different structures, such as the vestibular system, and the muscle and joint receptors of the neck. Damage of even one of these structures can lead to abnormal postural reflexes. We describe a case of a woman with a left pontine ischaemia who developed a 'dystonic' extensor posture of the left limbs while turned on the right side. This clinical picture differs from previous reports on the subject, and may relate to ischaemic damage of a pontine structure involved in posture control, or of adjacent neural connections to be yet identified. To the best of our knowledge, this is the first case reported in the literature. Clinical examples of an altered interplay between vestibular and neck receptors are rare.
Topics: Aged, 80 and over; Decerebrate State; Female; Humans; Ischemia; Neck; Pons; Posture; Reflex, Abnormal; Seizures; Sleep Stages; Tomography, X-Ray Computed; Vestibule, Labyrinth
PubMed: 26561222
DOI: 10.1136/bcr-2015-210616 -
The Journal of Physiology Jan 2012Recently, transgenic mice have been created with mutations affecting the components of the mammalian spinal central pattern generator (CPG) for locomotion; however, it...
Recently, transgenic mice have been created with mutations affecting the components of the mammalian spinal central pattern generator (CPG) for locomotion; however, it has currently only been possible to evoke fictive locomotion in mice, using neonatal in vitro preparations. Here, we demonstrate that it is possible to evoke fictive locomotion in the adult decerebrate mouse in vivo using l-3,4-dihydroxyphenylalanine methyl ester hydrochloride (l-DOPA) and 5-hydroxytryptophan (5HTP) following injection of the monoaminoxiadase inhibitor Nialamide. We investigate the effects of afferent stimulation and spinalization as well as demonstrate the possibility of simultaneous intracellular recording of rhythmically active motoneurones. Our results demonstrate that several features of the mouse locomotor CPG are similar to those that have been observed in rat, cat, rabbit and monkey suggesting a fairly conserved organisation and allowing for future results in transgenic mice to be extrapolated to existing knowledge of CPG components and circuitry obtained in larger species.
Topics: 5-Hydroxytryptophan; Animals; Cats; Decerebrate State; Electric Stimulation; Female; Haplorhini; Levodopa; Locomotion; Mice; Mice, Inbred C57BL; Mice, Transgenic; Models, Animal; Monoamine Oxidase Inhibitors; Motor Neurons; Neuronal Plasticity; Nialamide; Peripheral Nerves; Rabbits; Rats; Reaction Time; Spinal Cord
PubMed: 22106172
DOI: 10.1113/jphysiol.2011.214643 -
The Journal of Physiology Oct 2002We aimed in this study to elucidate the discharge properties and neuronal mechanisms of the dissociation between hypoglossal and phrenic inspiratory activities in...
We aimed in this study to elucidate the discharge properties and neuronal mechanisms of the dissociation between hypoglossal and phrenic inspiratory activities in decerebrate rats, which had been subjected to neuromuscular blockade and artificially ventilated. The discharge of the hypoglossal nerve and the intracellular activity of hypoglossal motoneurones were monitored during respiration and fictive-swallowing evoked by electrical stimulation of the superior laryngeal nerve, and were compared with the activity of the phrenic nerve. The hypoglossal nerve activity was characterized by its onset preceding the phrenic nerve activity ('pre-I' activity). By manipulating artificial respiration, we could augment the 'pre-I' activity, and could elicit another type of hypoglossal activity decoupled from the phrenic-associated inspiratory bursts ('decoupled' activity). We further scrutinized the correlatives of 'pre-I' and 'decoupled' activities in individual hypoglossal motoneurones. Hypoglossal motoneurones consisted of inspiratory (n = 42), expiratory (n = 18) and non-respiratory (n = 1) neurones and were classified by their swallowing activity into depolarized, hyperpolarized, hyperpolarized-depolarized and unresponsive groups. All of the inspiratory neurones were depolarized in accordance with the 'pre-I' and 'decoupled' activities, and all of the expiratory neurones were hyperpolarized during these activities. Fictive swallowing, which was characterized by its frequent emergence just after the phrenic inspiratory activity, was also evoked just after the 'decoupled' hypoglossal activity, suggesting that this activity may have similar effects on swallowing as the 'overt' inspiratory activity. Such a coupling between 'decoupled' and swallowing activities was also revealed in each motoneurone. These findings suggest that the 'pre-I' and 'decoupled' activities may reflect some internal inspiratory activity of the respiratory centre and that hypoglossal motoneurones may be driven by a distinct group of premotor neurones that possibly play a role in the coordination of respiration and swallowing.
Topics: Animals; Decerebrate State; Deglutition; Electric Stimulation; Electrophysiology; Hypoglossal Nerve; Laryngeal Nerves; Male; Motor Neurons; Phrenic Nerve; Rats; Respiratory Physiological Phenomena
PubMed: 12356891
DOI: 10.1113/jphysiol.2002.022566 -
The Journal of Physiology Jul 19661. In cats anaesthetized with chloralose whose spinal cords were transected 6-7 weeks previously, spontaneous contractions of the bladder had no effect on mono- or...
1. In cats anaesthetized with chloralose whose spinal cords were transected 6-7 weeks previously, spontaneous contractions of the bladder had no effect on mono- or polysynaptic reflexes recorded electrically from the cut lumbar ventral spinal roots.2. In the same cats contractions of the bladder decreased hind-limb extensor and flexor reflexes recorded myographically.3. The effects of (a) pelvic nerve stimulation and distension of the bladder on mono- and polysynaptic reflexes and (b) the effects of bladder contractions on hind-limb reflexes recorded myographically in acute and chronic spinal, decerebrate and anaesthetized cats are discussed.4. The sites of interaction between vesical and somatic reflexes are discussed and further evidence is presented that bladder contractions affect the gamma-loop.
Topics: Animals; Cats; Cordotomy; Decerebrate State; Electric Stimulation; Electromyography; Nerve Tissue; Pelvis; Peripheral Nerves; Potentiometry; Reflex; Spinal Cord; Urinary Bladder
PubMed: 5229398
DOI: 10.1113/jphysiol.1966.sp007981 -
The Journal of Physiology Feb 19791. A combination of bilateral lesions within the nucleus parabrachialis medialis complex (n.p.b.m.) and bilateral vagotomy typically resulted in an apneustic respiratory...
1. A combination of bilateral lesions within the nucleus parabrachialis medialis complex (n.p.b.m.) and bilateral vagotomy typically resulted in an apneustic respiratory pattern in decerebrate and paralysed cats. Integrated efferent phrenic nerve activity was recorded as an index of the respiratory rhythm.2. Changes in components of this apneustic breathing cycle were evaluated in response to steady-state hypercapnia and hypoxia. The components evaluated were (a) the period of phrenic discharge (inspiratory time, T(I)), (b) the period of no detectable phrenic activity (expiratory time, T(E)), (c) the total duration of the apneustic respiratory cycle (T(TOT), the sum of T(I) and T(E)), and (d) the average height of the integrated phrenic nerve activity (apneustic depth).3. Elevations of P(A, CO2) from values below 45 torr to 50-60 torr, under both hyperoxic and normoxic conditions, resulted in significant elevations of T(I), T(E), T(TOT) and depth. Further P(A, CO2) elevations to approximately 70 torr caused no change, or frequently, a decrease in T(I), T(E) and T(TOT); the apneustic depth increased in most animals.4. Diminutions in P(A, O2) from normoxic to hypoxic levels at isocapnia typically caused an increase in apneustic depth and, concomitantly, significant decreases in T(I), T(E) and T(TOT).5. Pharmacological stimulation of the carotid chemoreceptors by intracarotid administration of 1.0-20 mug NaCN produced a premature onset of phrenic nerve activity if delivered during the expiratory period. Such NaCN administrations, delivered during the inspiratory phase, resulted in an augmentation of the integrated phrenic discharge and a premature termination of phrenic activity. Carotid sinus nerve section eliminated the response to NaCN administration.6. In experimental animals having bilateral carotid sinus nerve section, normoxic hypercapnia caused similar changes in the apneustic breathing pattern to those recorded in cats having intact carotid chemoreceptors. However, isocapnic hypoxia induced time-dependent changes in the pattern of phrenic discharge including diminutions in depth, an onset of gasping-type activity, or expiratory apnea.7. In a few animals, bilateral n.p.b.m. lesions and bilateral vagotomy resulted in expiratory apnea which was continuous as long as ventilation with air was maintained. This expiratory apnea was replaced by an apneustic breathing pattern following diminutions of P(A, O2) below 90 torr. This establishment of an apneustic breathing pattern by hypoxia was observed both in animals having intact, as well as sectioned, carotid sinus nerves. This expiratory apnea could also be terminated by a single apneustic inspiration following general somatic stimulation or, in cats having intact carotid chemoreceptors, following intracarotid NaCN administration.8. It is concluded that hypercapnia and hypoxia produce differential alterations of the apneustic breathing pattern in decerebrate cats. Further, the hypoxia-induced changes are considered to represent the net result of carotid chemoreceptor stimulation and brain stem depression. The results of this study are considered in the context of proposed mechanisms for phase-switching of the respiratory cycle.
Topics: Animals; Apnea; Brain Stem; Carbon Dioxide; Carotid Sinus; Cats; Chemoreceptor Cells; Decerebrate State; Female; Male; Neurons, Efferent; Oxygen; Partial Pressure; Phrenic Nerve; Respiration
PubMed: 430430
DOI: 10.1113/jphysiol.1979.sp012671 -
Journal of Neurology, Neurosurgery, and... Feb 1971An oscillating decerebrate tonicity following the clonus phase in electroplexy was found to occur in the upper limbs, their tendon reflexes and the jaw; this increased...
An oscillating decerebrate tonicity following the clonus phase in electroplexy was found to occur in the upper limbs, their tendon reflexes and the jaw; this increased with each expiration and decreased with inspiration. The times of these occurrences in the upper limbs were measured in groups where no anaesthesia, diazepam or methohexital were used. The mean times of their onset and end were related to other phenomena of ECT. The times of occurrence and duration of decerebrate tonicity were established and compared in the three cohorts. There was a definite relationship to the onset of respiratory rhythmicity in all three groups. The evidence for the existence of decerebrate tonicity and atonicity are discussed from experimental contributions and more recent clinical evidence of the clonus phase as an example of an oscillation between tonic and atonic decerebrate states. Further clinical and experimental data are discussed which show connections between the decerebrate state, cerebral and cerebellar functions, respiratory centres, brain-stem and gravity afferents during rest and locomotion. An explanation is offered that the oscillatory phenomena are probably a mechanism to aid respiration and motor efficiency.
Topics: Brain Stem; Cerebellum; Decerebrate State; Depression; Diazepam; Electroconvulsive Therapy; Forearm; Humans; Jaw; Locomotion; Methohexital; Muscle Contraction; Muscle Tonus; Muscles; Reflex, Stretch; Respiration; Rest
PubMed: 5551693
DOI: 10.1136/jnnp.34.1.32 -
The Journal of Physiology Jun 19931. We examined the interaction between central pattern generators for respiration and deglutition in decerebrate, vagotomized, paralysed and ventilated cats (n = 10), by...
1. We examined the interaction between central pattern generators for respiration and deglutition in decerebrate, vagotomized, paralysed and ventilated cats (n = 10), by recording activity from the following nerves: hypoglossal, phrenic, thyroarytenoid and triangularis sterni. Fictive breathing was spontaneous with carbon dioxide above the apnoeic threshold (end-tidal PCO2, 32 +/- 4 mmHg) and fictive swallowing was induced by stimulating the internal branch of the left superior laryngeal nerve (SLN) continuously (0.2 ms pulse duration, 10 Hz). 2. In all ten animals, SLN stimulation evoked short bursts of thyroarytenoid and hypoglossal nerve activity indicative of fictive swallowing. In two of ten animals, respiration was inhibited completely during deglutition. In the other eight animals, fictive breathing and swallowing occurred simultaneously. 3. With SLN stimulation below threshold for eliciting swallowing, the respiratory rhythm decreased, the duration of inspiration did not change but the duration of expiration, especially stage II, increased. Integrated nerve activities indicated that the rate of rise and peak of phrenic nerve activity decreased, stage I expiratory activity of the thyroarytenoid and especially that of the hypoglossal nerve increased and stage II expiratory activity of the triangularis sterni nerve was suppressed completely. However, if inspired carbon dioxide was increased, i.e. hypercapnic ventilation, stage II expiratory activity remained partially during continuous SLN stimulation. 4. Fictive-swallowing bursts occurred only at respiratory phase transitions. At the minimal stimulus intensity that evoked repetitive swallowing bursts, the pattern of interaction between breathing and swallowing central pattern generators was consistent for each animal (n = 7) but was different across animals. In four animals, fictive swallows occurred at the phase transition between stage II expiration and inspiration, at the transition between inspiration and stage I expiration in one animal; and in two other animals, at the transition between stage I and II of expiration. 5. The response to SLN stimulation accommodated during the stimulus train. Accommodation was evident in both the interswallow interval (ISI) which lengthened, and the interaction pattern which had fewer swallows per breath as the stimulus period progressed. In contrast to the ISI, characteristics of the fictive swallow did not accommodate. For example, duration of the swallow was constant, distributed over a narrow range throughout the stimulus train. 6. We conclude that the central pattern generators for swallowing and breathing interact. The pattern of interaction supports the three-phase theory of respiratory pattern generation.(ABSTRACT TRUNCATED AT 400 WORDS)
Topics: Animals; Cats; Decerebrate State; Deglutition; Electric Stimulation; In Vitro Techniques; Laryngeal Nerves; Models, Biological; Motor Neurons; Pharyngeal Muscles; Respiratory Mechanics; Vagotomy
PubMed: 8229859
DOI: 10.1113/jphysiol.1993.sp019702