scholarly journals Carotid sinus nerve section abolishes NMDA evoked respiratory effects in anaesthetised rats

2005 ◽  
Vol 145 (2-3) ◽  
pp. 127-134
Author(s):  
Katarzyna Kaczyńska ◽  
Małgorzata Szereda-Przestaszewska
Keyword(s):  
Carotid Sinus ◽  
Carotid Sinus Nerve ◽  
Nerve Section ◽  
Respiratory Effects ◽  
Anaesthetised Rats

Carotid bifurcation sympathectomy and deafferentation: respiration during hypercapnia

1988 ◽  
Vol 255 (2) ◽  
pp. R252-R258
Author(s):  
D. B. Jennings ◽  
P. C. Szlyk
Keyword(s):  
Carotid Sinus ◽  
Carotid Bifurcation ◽  
The Other ◽  
Afferent Activity ◽  
Nerve Section ◽  
Absolute Level ◽  
Respiratory Effects ◽  
Percent Change ◽  
Fractional Concentration ◽  
Awake Cats

The respiratory effects of hypercapnia were studied in six awake cats 1) after bilateral sympathectomy of the carotid bifurcations and 2) after bilateral section of the carotid sinus nerves. When cats breathed either 2 or 4% CO2 in air, neither denervation affected the absolute level of ventilation, the percent change in ventilation, or the range of breath-to-breath variability in ventilation (V). However, in all six cats tidal volume (VT) increased for some levels of breath V after sympathectomy of the carotid bifurcations during inhalation of 4% CO2 in air. Moreover, after the subsequent carotid deafferentation, increased VT during fractional concentration of inspired CO2 (FICO2) of 4% persisted in four of six cats. Thus increased VT after sympathectomy could not be attributed to increased carotid chemoreceptor afferent activity but may have been due to reduced baroreceptor activity. On the other hand, sympathectomy-induced differences in breath timing, present during inhalation of 2% CO2, were reversed to intact values after sinus nerve section. In contrast to 2% CO2, changes in respiratory timing in intact cats associated with 4% CO2 were not altered significantly by sympathectomy or deafferentation of the carotid bifurcations. The latter indicates that above a critical FICO2 central mechanisms, unrelated to the carotid bifurcation, dominated respiratory timing in the hypercapnic awake cats.

scholarly journals Respiratory Effects of Division of the Carotid Sinus Nerve in the Lamb Soon After the Initiation of Breathing

1968 ◽  
Vol 2 (4) ◽  
pp. 264-270 ◽  
Author(s):  
H S Harned ◽  
R T Herrington ◽  
C A Griffin ◽  
W S Berryhill ◽  
L G MacKinney
Keyword(s):  
Carotid Sinus ◽  
Carotid Sinus Nerve ◽  
Respiratory Effects

Effects of decortication and carotid sinus nerve section on ventilation of the rat

1981 ◽  
Vol 43 (3) ◽  
pp. 263-273 ◽  
Author(s):  
M. Maskrey ◽  
D. Megirian ◽  
S.C. Nicol
Keyword(s):  
Carotid Sinus ◽  
Carotid Sinus Nerve ◽  
Nerve Section

The Effect of Acute Hyhoxia and Carotid Sinus Nerve Section on Hypothalamic Blood Flow in the Rabbit

1975 ◽  
Vol 49 (3) ◽  
pp. 11P-12P ◽  
Author(s):  
R. A. F. Linton ◽  
Roxana Miller ◽  
I. R. Cameron
Keyword(s):  
Blood Flow ◽  
Carotid Sinus ◽  
Carotid Sinus Nerve ◽  
Nerve Section

scholarly journals Carotid sinus nerve section and the increase in plasma cortisol during acute hypoxia in fetal sheep.

1994 ◽  
Vol 477 (1) ◽  
pp. 75-80 ◽  
Author(s):  
D A Giussani ◽  
H H McGarrigle ◽  
P J Moore ◽  
L Bennet ◽  
J A Spencer ◽  
...  
Keyword(s):  
Plasma Cortisol ◽  
Carotid Sinus ◽  
Acute Hypoxia ◽  
Carotid Sinus Nerve ◽  
Nerve Section ◽  
Fetal Sheep

Integration of chemoreceptor stimuli by rostral brainstem respiratory areas

1975 ◽  
Vol 39 (2) ◽  
pp. 209-214 ◽  
Author(s):  
W. M. Saint John ◽  
G. C. Bond ◽  
J. N. Pasley
Keyword(s):  
Tidal Volume ◽  
Respiratory Activity ◽  
Carotid Sinus ◽  
Minute Volume ◽  
Carotid Sinus Nerve ◽  
Nerve Section ◽  
Bilateral Vagotomy ◽  
Pneumotaxic Center ◽  
Decerebrate Cats ◽  
Paco2 Level

Ventilatory regulation by brainstem sites rostral to the midpontile level was assessed in decerebrate cats by comparing the effects of punctate pneumotaxic center lesions with those of midpontile transection. After either procedure, PACO2 was significantly elevated. Moreover an equal suppression of hypercapnia-induced minute volumes and maintenance, at some PACO2 levels, of minute volume responses to hypoxia was observed. Tidal volume elevations accounted for the maintenance of hypoxia-induced minute volumes. Following pneumotaxic center lesions, hypercapnia-induced tidal volumes were higher than those exhibited subsequent to midpontile transection. After carotid sinus nerve section, PACO2 was elevated and hypoxia-induced alterations were abolished. Bilateral vagotomy resulted in apneusis. These data demonstrate that, in the brainstem area examined, only the pneumotaxic center influences the PACO2 level or set point for respiratory activity. A locus of tidal volume generation is ascribed to rostral brainstem sites outside this pneumotaxic center. Data obtained support the hypothesis of a differential brainstem integration of peripheral and central chemoreceptor afferent stimuli.

Respiration in awake cats: sympathectomy and deafferentation of carotid bifurcations

1987 ◽  
Vol 62 (3) ◽  
pp. 932-940 ◽  
Author(s):  
P. C. Szlyk ◽  
D. B. Jennings
Keyword(s):  
Carotid Sinus ◽  
Minute Ventilation ◽  
Reflex Modulation ◽  
Carotid Sinus Nerve ◽  
Inspiratory Time ◽  
Nerve Section ◽  
Arterial Pco2 ◽  
Bilateral Carotid ◽  
Arterial Po2 ◽  
Awake Cats

Respiratory effects of sympathectomy of the carotid bifurcations and, in a subsequent experiment, bilateral carotid sinus nerve section were examined in six awake resting cats. In each intact and denervated state, sequential breaths were analyzed at 10-min intervals up to 80 min. Individual breath frequency (f), tidal volume (VT), and ventilation (V = f X VT) were determined. In individual cats, sympathectomy or deafferentation could cause significant increases or decreases in ventilation or no change. Thus the range of spontaneous variability in breath V as well as minute ventilation (VE), averaged for the group, were not consistently altered in the same direction by either sympathectomy or deafferentation of the carotid bifurcations. Interestingly, in most cats after both sympathectomy (5 of 6) and deafferentation (4 of 6), VT increased and f decreased relative to V. Despite this, after sinus nerve section in two cats arterial PO2 decreased and arterial PCO2 tended to increase relative to VE, suggesting possible effects of deafferentation on ventilation-perfusion balance. Sympathectomy also affected timing such that inspiratory time began to exceed 0.5 of the breath duration at a lower breath f; this effect of sympathectomy was reversed to intact values by subsequent sinus deafferentation. Thus, in eupneic awake cats, sympathetics normally suppress reflex modulation of central timing from carotid chemoreceptors and/or baroreceptors.

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