scholarly journals Role of the Telencephalon in the Synchronization of Locomotor and Respiratory Frequencies During Walking in Canada Geese

1989 ◽  
Vol 145 (1) ◽  
pp. 283-301 ◽  
Author(s):  
GREGORY D. FUNK ◽  
WILLIAM MILSOM ◽  
GERALD N. SHOLOMENKO ◽  
JOHN D. STEEVES
Keyword(s):  
Oxygen Uptake ◽  
Minute Ventilation ◽  
Work Rate ◽  
Canada Geese ◽  
Breathing Frequency ◽  
Medullary Reticular Formation ◽  
Co2 Output ◽  
The Relationship ◽  
Respiratory Rhythms

To elucidate the importance of telencephalic structures and the effects of metabolic rate in the production of locomotor-respiratory coupling, we examined the relationship between locomotor and ventilatory patterns in: (1) intact trained geese, and (2) brainstem-stimulated (medullary reticular formation) decerebrate geese, that were walking on a treadmill. The decerebrate geese, however, were not completely self supporting. Thus, while the two groups walked with similar stride frequencies (fs), they did so at two different work rates. While at rest, tidal volume (VT), breathing frequency (fv) and minute ventilation (VE) were very similar in the two groups. VE increased 120% during walking in the intact geese, primarily as a result of increases VE, while both VT and fv increased to produce a smaller 40 % increase in VE in the decerebrate birds. Although the magnitude of the increase in VE was three times greater in the intact geese, the relationships between VE and oxygen uptake (VO2) and VE and CO2 output (VCOCO2) were similar in the two groups. Significant coupling between locomotor and respiratory patterns was found in both intact (28.3%) and decerebrate birds (28.9%), suggesting that the telencephalon is not essential for the coupling of locomotor and respiratory rhythms during walking in geese. In addition, the incidence of locomotor-respiratory synchrony was virtually identical in the two groups in spite of a threefold difference in metabolic work rate.

Ventilatory response to moderate and severe hypoxia in adult dogs: role of endorphins

1988 ◽  
Vol 65 (3) ◽  
pp. 1383-1388 ◽  
Author(s):  
J. I. Schaeffer ◽  
G. G. Haddad
Keyword(s):  
Ventilatory Response ◽  
Minute Ventilation ◽  
Severe Hypoxia ◽  
Moderate Hypoxia ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Before And After ◽  
The Relationship ◽  
Arterial Po2

To determine the role of opioids in modulating the ventilatory response to moderate or severe hypoxia, we studied ventilation in six chronically instrumented awake adult dogs during hypoxia before and after naloxone administration. Parenteral naloxone (200 micrograms/kg) significantly increased instantaneous minute ventilation (VT/TT) during severe hypoxia, (inspired O2 fraction = 0.07, arterial PO2 = 28-35 Torr); however, consistent effects during moderate hypoxia (inspired O2 fraction = 0.12, arterial PO2 = 40-47 Torr) could not be demonstrated. Parenteral naloxone increased O2 consumption (VO2) in severe hypoxia as well. Despite significant increases in ventilation post-naloxone during severe hypoxia, arterial blood gas tensions remained the same. Control studies revealed that neither saline nor naloxone produced a respiratory effect during normoxia; also the preservative vehicle of naloxone induced no change in ventilation during severe hypoxia. These data suggest that, in adult dogs, endorphins are released and act to restrain ventilation during severe hypoxia; the relationship between endorphin release and moderate hypoxia is less consistent. The observed increase in ventilation post-naloxone during severe hypoxia is accompanied by an increase in metabolic rate, explaining the isocapnic response.

The relationship between oxygen uptake reserve and heart rate reserve is affected by intensity and duration during aerobic exercise at constant work rate

2011 ◽  
Vol 36 (6) ◽  
pp. 839-847 ◽  
Author(s):  
Felipe A. Cunha ◽  
Adrian W. Midgley ◽  
Walace D. Monteiro ◽  
Felipe K. Campos ◽  
Paulo T.V. Farinatti
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Exercise Testing ◽  
Exercise Intensity ◽  
Maximal Exercise ◽  
Work Rate ◽  
Heart Rate Reserve ◽  
Constant Work Rate ◽  
The Stability ◽  
The Relationship

The relationship between the percentage of heart rate reserve (%HRR) and percentage of oxygen uptake reserve (%VO2R) has been recommended for prescribing aerobic exercise intensity. However, this relationship was derived from progressive maximal exercise testing data, and the stability of the relationship during prolonged exercise at a constant work rate has not been established. The main aim of this study was to investigate the stability of the %VO2R–%HRR relationship during prolonged treadmill exercise bouts performed at 3 different constant work rates. Twenty-eight men performed 4 exercise tests: (i) a ramp-incremental maximal exercise test to determine maximal heart rate (HRmax) and maximal oxygen uptake (VO2max) and (ii) three 40-min exercise bouts at 60%, 70%, and 80% VO2R. HR and VO2 significantly increased over time and were influenced by exercise intensity (p < 0.001 and p = 0.004, respectively). A 1:1 relationship between %HRR and %VO2R, and between %HRR and %VO2max, was not observed, with mean differences of 8% (t = 5.2, p < 0.001) and 6% (t = 4.8, p < 0.001), respectively. The VO2 values predicted from the ACSM running equation were all significantly higher than the observed VO2 values (p < 0.001 for all comparisons), whereas a difference for HR was observed only for the tenth min of exercise at 80% VO2R (p = 0.041). In conclusion, the main finding of this study was that the %HRR–%VO2R relationship determined by linear regression, obtained from progressive maximal exercise testing, did not apply to prolonged treadmill running performed at 3 work rates.

Anaerobic threshold alterations caused by endurance training in middle-aged men

1979 ◽  
Vol 46 (6) ◽  
pp. 1039-1046 ◽  
Author(s):  
J. A. Davis ◽  
M. H. Frank ◽  
B. J. Whipp ◽  
K. Wasserman
Keyword(s):  
Endurance Training ◽  
Anaerobic Threshold ◽  
Minute Ventilation ◽  
Correlation Coefficients ◽  
Cycle Ergometer ◽  
Work Rate ◽  
Middle Aged ◽  
Co2 Output ◽  
Before And After ◽  
Cycle Endurance

Nine previously sedentary middle-aged males underwent cycle endurance training 45 min/day for 9 wk with an average attendance of 4.1 days/wk. Seven males served as controls. Before and after the training period, the subjects performed three cycle ergometer tests. Work rate was incremented by 15 W/min, to the limit of the subjects' tolerance, in the first two tests; the third test consisted of contant-load cycling at an O2 uptake (VO2) just below the pretraining anaerobic threshold (AT). After training, the AT increased significantly by 44%, expressed as absolute VO2, and by 15%, expressed relative to VO2 max. Significant increases were also noted in VO2max (25%), maximal minute ventilation (19%), and maximal work rate (28%). The test-retest correlation coefficients for the AT (%VO2max) were 0.91, pre- and posttraining. Training did not alter steady-state VO2 during the submaximal exercise test whereas significant decreases occurred in CO2 output, VE, respiratory quotient, and VE/VO2. No changes occurred in the control subjects during this period. These results demonstrate that the AT is profoundly influenced by endurance training in previously sedentary middle-aged males.

Coordination of wingbeat and respiration in birds. II. "Fictive" flight

1992 ◽  
Vol 73 (3) ◽  
pp. 1025-1033 ◽  
Author(s):  
G. D. Funk ◽  
J. D. Steeves ◽  
W. K. Milsom
Keyword(s):  
Respiratory Activity ◽  
Cardiovascular Responses ◽  
Canada Geese ◽  
Free Flight ◽  
Wingbeat Frequency ◽  
Pekin Ducks ◽  
Before And After ◽  
The Relationship ◽  
Respiratory Rhythms ◽  
Central Level

To determine whether an interaction between central respiratory and locomotor networks may be involved in the observed coordination of wingbeat and respiratory rhythms during free flight in birds, we examined the relationship between wingbeat and respiratory activity in decerebrate Canada geese and Pekin ducks before and after paralysis. Locomotor activity was induced through electrical stimulation of brain stem locomotor regions. Respiratory frequency (fv) was monitored via pneumotachography and intercostal electromyogram recordings before paralysis and via intercostal and cranial nerve IX electroneurogram recordings after paralysis. Wingbeat frequency (fW) was monitored using pectoralis major electromyogram recordings before, and electroneurogram recordings after, paralysis. Respiratory and cardiovascular responses of decerebrate birds during active (nonparalyzed) and “fictive” (paralyzed) wing activity were qualitatively similar to those of a variety of vertebrate species to exercise. As seen during free flight, wingbeat and respiratory rhythms were always coordinated during electrically induced wing activity. Before paralysis during active wing flapping, coupling ratios (fW/fv) of 1:1, 2:1, 3:1, and 4:1 (wingbeats per breath) were observed. After paralysis, fW and fv remained coupled; however, 1:1 coordination predominated. All animals tested (n = 9) showed 1:1 coordination. Two animals also showed brief periods of 2:1 coupling. It is clear that locomotor and respiratory networks interact on a central level to produce a synchronized output. The observation that the coordination between fW and fv differs in paralyzed and nonparalyzed birds suggests that peripheral feedback is involved in the modulation of a centrally derived coordination.

A comparison of the visual analogue scale and modified Borg scale for the measurement of dyspnoea during exercise

1989 ◽  
Vol 76 (3) ◽  
pp. 277-282 ◽  
Author(s):  
Rachel C. Wilson ◽  
P. W. Jones
Keyword(s):  
Visual Analogue Scale ◽  
Analogue Scale ◽  
Minute Ventilation ◽  
Normal Subjects ◽  
Work Rate ◽  
Borg Scale ◽  
Exercise Tests ◽  
Vas Score ◽  
The Mean ◽  
The Relationship

1. The intensity of breathlessness during exercise was measured in ten normal subjects using a visual analogue scale (VAS) and a Borg scale to compare the use of the scales and their repeatability, both within the duration of a period of exercise and between tests. For each scale, subjects performed two exercise tests separated by a period of 2–6 weeks. Each exercise test consisted of two cycles of progressively increasing and decreasing workload. 2. All subjects felt confidently able to use both scales to quantify their feelings of breathlessness exclusively of other sensation. Equal preference was expressed for use of a particular scale. 3. With both scales there was a large intersubject variation in the relationship between dyspnoea score and minute ventilation (VE) (P < 0.01), and in the range of the scale used. 4. There was a good correlation between the VAS and Borg scores at each level of VE (r2 = 0.71), but the VAS score was used over a wider range than the Borg score. 5. The relationship between VE and the dyspnoea score measured by the two techniques was predominantly linear. The mean r2 for VAS score/VE was 0.68 (sd 0.19) and for Borg score/VE the mean r2 was 0.75 (sd 0.13). 6. The relationships VAS score/VE and Borg score/VE were unaffected by the direction in which the workload was varied (P > 0.05). 7. VE, measured at each work rate, did not differ between the two cycles (P > 0.05) or between the 2 days (P > 0.05). 8. With both scales, the slope of the VE-breathlessness relationship was slightly higher during the second half of the exercise compared with the first (0.05 < P > 0.01). 9. The scores with both scales were lower in the second test compared with the first (P < 0.01): Borg 16% lower, VAS 27% lower. 10. Measurements of dyspnoea made with the Borg scale appeared to have greater stability than VAS measurements and to correlate with VE a little better.

Brain ECF pH and central chemical control of ventilation during anoxia in turtles

1987 ◽  
Vol 252 (5) ◽  
pp. R848-R852 ◽  
Author(s):  
D. G. Davies ◽  
J. A. Sexton
Keyword(s):  
Ventilatory Response ◽  
Minute Ventilation ◽  
Control Period ◽  
Extracellular Fluid ◽  
Blood Gases ◽  
Breathing Frequency ◽  
Arterial Blood Gases ◽  
Brain Extracellular Fluid ◽  
Arterial Blood

The role of changes in brain extracellular fluid [H+] in the control of breathing during anoxia was studied in unanesthetized turtles, Chrysemys scripta. Ventilation, [minute ventilation (VE), tidal volume (VT), and breathing frequency (f)], cerebral extracellular fluid (ECF) pH, and arterial blood gases were measured at 25 degrees C during a 30-min control period (room air), 30 min of anoxia (100% N2 breathing), and 60 min of recovery (room air). ECF pH was measured in the cerebral cortex with a glass microelectrode (1-2 micron tip diam). Large changes in ventilation, ECF [H+], and arterial blood gases were observed. The predominant ventilatory response was an increase in f with a slight increase in VT. A correlation was observed between ECF [H+] and f, which suggested that central chemoreceptor stimulation was involved in the ventilatory response.

Relationship between ventilatory response and body temperature during prolonged submaximal exercise

2006 ◽  
Vol 100 (2) ◽  
pp. 414-420 ◽  
Author(s):  
Keiji Hayashi ◽  
Yasushi Honda ◽  
Takeshi Ogawa ◽  
Narihiko Kondo ◽  
Takeshi Nishiyasu
Keyword(s):  
Body Temperature ◽  
Oxygen Uptake ◽  
Skin Temperature ◽  
Blood Lactate ◽  
Core Temperature ◽  
Core Body Temperature ◽  
Minute Ventilation ◽  
Submaximal Exercise ◽  
Rate Of Increase ◽  
The Relationship

We examined whether an increase in skin temperature or the rate of increase in core body temperature influences the relationship between minute ventilation (V̇e) and core temperature during prolonged exercise in the heat. Thirteen subjects exercised for 60 min on a cycle ergometer at 50% of peak oxygen uptake while wearing a suit perfused with water at 10°C (T10), 35°C (T35), or 45°C (T45). During the exercise, esophageal temperature (Tes), skin temperature, heart rate (HR), V̇e, tidal volume, respiratory frequency (f), respiratory gases, blood pressure (BP), and blood lactate were all measured. We found that oxygen uptake, carbon dioxide output, BP, and blood lactate did not differ among the sessions. Tes, HR, V̇e, and f remained nearly constant from minute 10 onward in the T10 session, but all of these parameters progressively increased in the T35 and T45 sessions, and significantly higher levels were seen in the T45 than the T35 session. For all but two subjects in the T35 and T45 sessions, plotting V̇e as a function of Tes revealed no threshold for hyperventilation; instead, increases in V̇e were linearly related to Tes, and there were no significant differences in the slopes or intercepts between the T35 and T45 sessions. Thus, during prolonged submaximal exercise in the heat, V̇e increases with core temperature, and the influences of skin temperature and the rate of increase in Tes on the relationship between V̇e and Tes are apparently small.

Effect of chronic pulmonary denervation on ventilatory responses to exercise

1986 ◽  
Vol 61 (2) ◽  
pp. 603-610 ◽  
Author(s):  
P. S. Clifford ◽  
J. T. Litzow ◽  
J. H. von Colditz ◽  
R. L. Coon
Keyword(s):  
Treadmill Exercise ◽  
Minute Ventilation ◽  
Breathing Frequency ◽  
Inspiratory Time ◽  
Pressure Transducers ◽  
Ventilatory Responses ◽  
The Third ◽  
Exercise Challenge ◽  
Before And After

To assess the role of intrapulmonary receptors on the ventilatory responses to exercise we studied six beagle dogs before and after chronic pulmonary denervation and five dogs before and after sham thoracotomies. Each exercise challenge consisted of 6 min of treadmill exercise with measurements taken during the third minute at 3.2 km/h, 0% grade, and during the third minute at 5.0 km/h, 0% grade. Inspiratory and expiratory airflows were monitored with a low-dead-space latex mask and pneumotachographs coupled to differential pressure transducers. Both pre- and postsurgery, all dogs exhibited a significant arterial hypocapnia and alkalosis during exercise. Denervation of the lungs had no significant effect on minute ventilation at rest or during exercise, although there was a lower frequency and higher tidal volume in the lung-denervated dogs at all measurement periods. Breathing frequency increased significantly during exercise in lung-denervated dogs but to a lesser magnitude than in the control dogs. The changes that occurred in breathing frequency in all animals were due predominantly to the shortening of expiratory time. Inspiratory time did not shorten significantly during exercise following lung denervation. We conclude from these data that intrapulmonary receptors which are deafferented by sectioning the vagi at the hilum are not responsible for setting the level of ventilation during rest or exercise but are involved in determining the pattern of breathing.

Sign in / Sign up

Export Citation Format

Share Document