Peak Discharge
Mostrando 25-36 de 136 artigos, teses e dissertações.
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25. Response characteristics of pulmocutaneous arterial baroreceptors in the toad, Bufo marinus.
1. Response characteristics of baroreceptors with receptive fields in the pulmocutaneous artery (p.c.a.) were determined in pithed toads by applying pressure steps, ramps, sine waves, and volume infusions into the vascularly isolated and perfused p.c.a. 2. The baroreceptors exhibited phasic and tonic discharge thresholds (30.3 +/- 2.3 and 36.2 +/- 2.8 mmHg r
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26. Maturation of carotid chemoreceptor sensitivity to hypoxia: in vitro studies in the newborn rat.
1. A preparation was developed to record single-fibre chemoreceptor afferent activity from carotid bodies of newborn and adult rats in vitro. The response to severe hypoxia was studied as a function of developmental age in four age groups: 1-2, 4-7, 10-15 days and adult (25-30 days). 2. During superfusion with HEPES-saline at room PO2 and at 26 or 35 degrees
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27. Caudal medullary expiratory neurone and internal intercostal nerve discharges in the cat: effects of lung inflation.
In midcollicular decerebrate, thoracotomized, paralysed cats that were ventilated by a cycle-triggered pump and had an expiratory load, recordings were taken from expiratory neurones in the nucleus retroambigualis of the caudal medulla and from the internal intercostal nerves at T8-T9 levels. Expiratory neurone and internal intercostal activities had augment
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28. Differential activation of motor units in the wrist extensor muscles during the tonic vibration reflex in man.
1. Single motor unit activity was recorded in the extensor carpi radialis longus and extensor carpi radialis brevis muscles of five healthy human subjects, using metal microelectrodes. 2. Motor units were characterized on the basis of their twitch contraction times and their force recruitment thresholds during voluntary imposed-ramp contractions. 3. The disc
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29. Cardiac arrhythmias 48 hours before, during, and 48 hours after discharge from hospital following acute myocardial infarction.
The cardiac rate and rhythm were studied by 24-hour ambulatory electrocardiographic recording in 44 patients before, during, and after being discharged from hospital following an acute myocardial infarction. The first recordings were started 48 hours before discharge, the second on the morning of the day of discharge, and the third 48 hours after discharge (
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30. Estimating the strength of common input to human motoneurons from the cross-correlogram.
1. The relationship between the motor unit discharge pattern (rate and variability) and synchronization of motor unit pairs was studied in the first dorsal interosseus muscle of human subjects. In separate trials of up to 4 min duration, subjects voluntarily controlled the mean discharge rate of an identified motor unit at one of several prescribed rates (ra
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31. Discharge of vagal pulmonary receptors differentially alters neural activities during various stages of expiration in the cat.
1. The purpose was to evaluate the hypothesis that neural expiration is composed of two phases: I, a post inspiratory period; and II, the period at which expiratory activities of spinal nerves reach peak values. We hypothesized that the discharge of pulmonary stretch receptors might differentially alter neural activities during these two phases. 2. Activitie
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32. Compared effects of serotonin on cervical and hypoglossal inspiratory activities: an in vitro study in the newborn rat.
1. Experiments were performed on the brain stem-spinal cord preparation of newborn rats, in which the phrenic and hypoglossal nerves continue to show rhythmic respiratory activity in vitro, in order to compare the effects of serotonin (5-HT) on both activities and to analyse the mechanisms responsible for the depression by 5-HT of the hypoglossal activity. 2
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33. Changes in discharge rate of fusimotor neurones provoked by fatiguing contractions of cat triceps surae muscles.
1. Changes in discharge rate of thirty-one fusimotor neurones to triceps surae muscles during long-lasting, fatiguing contractions of these muscles were studied in decerebrate cats. Discharges of fusimotor neurones were recorded from the nerve filaments. Muscle contractions were elicited by electrical stimulation of either the muscle nerves (twenty-one neuro
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34. Effects of ouabain on carotid body chemoreceptor activity in the cat.
The effects of infusions of ouabain on chemoreceptor activity recorded from the peripheral end of a sectioned carotid sinus nerve were studied in cats anaesthetized with pentobarbitone. Ouabain caused a marked increase in chemoreceptor discharge followed by a decline in discharge to frequencies near or below the pre-ouabain level; during the latter period fu
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35. Respiratory-related discharge pattern of sympathetic nerve activity in the spontaneously hypertensive rat.
1. Synchronization of spontaneous sympathetic discharge during the respiratory cycle was studied in the cervical and renal nerves of vagotomized, normotensive Wistar-Kyoto rats (WKYs) and age-matched spontaneously hypertensive rats (SHRs). Phrenic nerve discharge was used as an index of central inspiratory activity. 2. In normotensive Wistar-Kyoto rats depre
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36. Discharges of interpositus and Purkinje cells of the cat cerebellum during locomotion under different conditions.
1. Extracellular microelectrodes were used in free-to-move cats to study the locomotor-related discharges of Purkinje cells in the intermediate part of lobule V of the cerebellar anterior lobe and of neurones in the underlying nucleus interpositus anterior. All cells studied discharged rhythmically during locomotion. 2. The discharges during walking at a spe