Statistical analysis of cyclic variations in carotid body chemoreceptor activity.

Gehrich, John L.; Ge, Moore

doi:10.1152/jappl.1973.35.5.642

Cited by 22 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our observation that the shape and size of the response to a pure Pco2 alternation is independent of the steady background Po2 agrees with that of Band & Wolff (1978) who measured the amplitudes of oscillations of chemoreceptor discharge in freely breathing, chemodenervated cats at different levels of inspired P02. It also agrees with the observations of Gehrich & Moore (1973), and broadly with Goodman et al (1974), but does so in a preparation in which (i) there was no variation in the amplitude or period of the PcO2 waveform, and (ii) there were no Po2 oscillations occurring simultaneously. Lahiri, Mulligan & Mokashi (1982) appeared to contradict the above results when they showed that adaptation of the discharge of chemoreceptors after a change in PC0 is greater in hypoxia than in normoxia.…”

Section: Responses To Simple Alternations At Different Steady Backgrosupporting

confidence: 91%

“…It also agrees with the observations of Gehrich & Moore (1973), and broadly , but does so in a preparation in which (i) there was no variation in the amplitude or period of the PcO2 waveform, and (ii) there were no Po2 oscillations occurring simultaneously. Lahiri, Mulligan & Mokashi (1982) appeared to contradict the above results when they showed that adaptation of the discharge of chemoreceptors after a change in PC0 is greater in hypoxia than in normoxia.…”

Section: Stability Of the Preparationsupporting

confidence: 90%

See 1 more Smart Citation

Do oxygen tension variations contribute to the respiratory oscillations of chemoreceptor discharge in the cat?

Kumar¹,

Nye²,

Torrance³

1988

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. A high-frequency high-flow ventilator has been developed which will produce abrupt changes in alveolar gas tensions. We have used it to study the individual contributions of Pco and Po2 in producing the oscillations which occur in the discharge of carotid chemoreceptors in the cat with respiration, by producing repeated end-tidal alternations (i) of Pco in constant hypoxia, (ii) of PO in constant normocapnia and (iii) of both Po and Pco2' i.e. of asphyxia.2. The chemoreceptor response to alternations of Pco was always brisker than that to alternations of Po at 2, 4 or 8 s cycle durations.3. An increase in the frequency of the alveolar alternation shortened the difference between the response times to Pco2 and PO2 but it increased the phase difference between the stimulus and the response waveforms.4. With 4 s cycles, in normocapnic hypoxia, Pco was 2-9 times more effective (impulses s-1 Torr-1) than PO in producing oscillations in discharge.5. The oscillations in discharge to simultaneous alternations of Po2 and Pco2 were not significantly different from the sum of individual oscillations to alternations of PC0 and of PO alone. This was true with respect to timing and to amplitude of the oscillation.6. Usually the amplitude of the chemoreceptor discharge oscillation in response to an asphyxial alternation was greater than the amplitude of the oscillation to either its PCO2 or its Po2 component alone. However, at the highest frequencies used, the phase relation between the Pco and PO components of the response could lead to the summed asphyxial response being less than its individual components.7. The amplitudes and shapes of the oscillations in response to 4 s Pco2 alternations were not affected by changing either the steady-background PO2 or Pco2, but the amplitudes of the oscillations to pure Po2 alternations were enhanced by hypoxia and by hypercapnia. The importance of PO2 and Pco2 in giving rise to the natural respiratory oscillations in chemoreceptor discharge depends on the mean levels of the two gases. In normocapnic hypoxia (Po2 ca. 50 Torr) they are equally important but when PO is raised it becomes less important.

show abstract

Section: Responses To Simple Alternations At Different Steady Backgrosupporting

confidence: 91%

Section: Stability Of the Preparationsupporting

confidence: 90%

Do oxygen tension variations contribute to the respiratory oscillations of chemoreceptor discharge in the cat?

Kumar¹,

Nye²,

Torrance³

1988

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…A similar result was previously obtained from the analysis of afferent spike generation of rat chemoreceptors in vitro (5) and one single-fiber recording of mouse chemoreceptors in vivo (4). In other species, interspike intervals also approximate a random process having a mean frequency that is modulated by the respiratory and cardiac cycles (15). Of course, this modulation would be absent in vitro.…”

Section: Discussionsupporting

confidence: 79%

Single-unit recordings of arterial chemoreceptors from mouse petrosal ganglia in vitro

Donnelly

Rigual

2000

Journal of Applied Physiology

View full text Add to dashboard Cite

A preparation was developed that allows for the recording of single-unit chemoreceptor activity from mouse carotid body in vitro. An anesthetized mouse was decapitated, and each carotid body was harvested, along with the sinus nerve, glossopharyngeal nerve, and petrosal ganglia. After exposure to collagenase/trypsin, the cleaned complex was transferred to a recording chamber where it was superfused with oxygenated saline. The ganglia was searched for evoked or spontaneous unit activity by using a glass suction electrode. Single-unit action potentials were 57 +/- 10 (SE) (n = 16) standard deviations above the recording noise, and spontaneous spikes were generated as a random process. Decreasing superfusate PO(2) to near 20 Torr caused an increase in spiking activity from 1. 3 +/- 0.4 to 14.1 +/- 1.9 Hz (n = 16). The use of mice for chemoreceptor studies may be advantageous because targeted gene deletions are well developed in the mouse model and may be useful in addressing unresolved questions regarding the mechanism of chemotransduction.

show abstract

“…The fluctuations in chemoreceptor activity that have been recorded from singleor few-fibre preparations of the carotid sinus nerve under normoxic conditions have usually been found to be large relative to the mean discharge frequency. Fluctuations which were 30 %, or more, of the mean have been reported by a number of authors (Biscoe & Purves, 1967;Gehrich & Moore, 1973;Goodman et al 1974;Band, McClelland, Phillips, Saunders & Wolff, 1978). Based on recordings of arterial pH oscillations (which are presumed to reflect oscillations in Pa, co2) Band et al (1978) deduced that Pa, co0 oscillations had an amplitude that was less than 10 % ofthe mean Pa C02 These authors concluded therefore that there was unlikely to be a simple proportional relationship between the fluctuations in chemoreceptor activity and oscillations in Pa CO2* For the chemoreceptors to respond purely in a proportional manner to P. co2 would require that they do so with high gain and high threshold.…”

Section: Discussionmentioning

confidence: 73%

“…This suggested that the changes in Pa, co, may be more important for the generation of the fluctuations in chemoreceptor activity. Further support for the contention that Pa co2 may be the more significant variable in the determination of the fluctuations in discharge can be drawn from the experiments of Gehrich & Moore (1973). These authors compared the patterns of chemoreceptor discharge obtained during inhalation of 8 % CO2 in 20 % 02-balance N2 with those obtained during inhalation of 10 % 02-90 % N2.…”

Section: Discussionmentioning

confidence: 99%

The effect of small changes in arterial carbon dioxide tension on carotid chemoreceptor activity in the cat.

Cross¹,

Leaver²,

Semple³

et al. 1986

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. The hypothesis that the fluctuations in carotid chemoreceptor discharge represent more than a simple proportional response to respiratory oscillations of Pa, co, has been examined.2. Simultaneous recordings of the activity in few-or multi-fibre chemoreceptor preparations of the cut carotid sinus nerve and oscillations of carotid arterial pH have been made in four anaesthetized cats which were paralysed and artificially ventilated at constant frequency.3. Chemoreceptor activity was averaged over a minimum of twenty consecutive pH cycles and the amplitude of the fluctuations in discharge frequency determined.4. Using the mean Pa, co obtained from blood-gas analysis and the slope of the relationship between log Pa co2 and pH obtained in each cat, the amplitude of the pH oscillations was converted to P., co, amplitude. This amplitude relative to the mean Pa co2 has been compared with the amplitude of the corresponding fluctuation in the chemoreceptor discharge frequency recorded from the carotid sinus nerve (c.s.n.d. amplitude) relative to its mean level. Whereas the Pa co2 amplitude was always less than 8 % of the mean Pa co, the c.s.n.d. amplitude ranged from 40 to 186 % of the mean discharge frequency.5. C.s.n.d. amplitude was divided by the corresponding Pa, co, amplitude to give an index of the sensitivity of the chemoreceptors to Pa co2. This sensitivity has been compared with that determined from the mean discharge frequency produced in response to changes in mean P,, co, comparable in magnitude to the Pa, co, amplitude.The former sensitivity was usually at least 3 times greater than the latter.6. Examination of the fluctuations in chemoreceptor discharge frequency in relation to the corresponding pH oscillations revealed that whereas the minimum discharge frequency coincided with the alkaline peak of the pH oscillation (trough of the Pa co2 oscillation), the maximum discharge frequency did not invariably coincide with the acid trough of the pH oscillation (peak of the P., co2 oscillation).On 30 % of occasions, the maximum discharge frequency was associated with the region of maximum rate of fall of pH (maximum rate of rise of Pa, co2).7. It was concluded that fluctuations in the discharge of carotid chemoreceptors cannot be accounted for on the basis of a simple proportional relationship to Pa, co..

show abstract

Statistical analysis of cyclic variations in carotid body chemoreceptor activity.

Cited by 22 publications

References 0 publications

Do oxygen tension variations contribute to the respiratory oscillations of chemoreceptor discharge in the cat?

Do oxygen tension variations contribute to the respiratory oscillations of chemoreceptor discharge in the cat?

Single-unit recordings of arterial chemoreceptors from mouse petrosal ganglia in vitro

The effect of small changes in arterial carbon dioxide tension on carotid chemoreceptor activity in the cat.

Contact Info

Product

Resources

About