Back to Search
Start Over
Effects of graded focal cold block in the solitary and para-ambigual regions of the medulla in the cat
- Source :
- Acta Physiologica Scandinavica. 124:317-328
- Publication Year :
- 1985
- Publisher :
- Wiley, 1985.
-
Abstract
- Unilateral focal cold blocks in the region of the nucleus tractus solitarius and the dorsal respiratory group of neurons, DRG, of anaesthetized cats consistently caused apneustic-type breathing. There was no concomitant change in the initial rate of rise of inspiratory activity. The apneustic prolongation of inspiratory duration, TI, was most pronounced in, but was not confined to, the DRG. The apneustic effects were more marked after vagotomy. In cats with intact vagus nerves being given artificial ventilation, focal cooling at certain sites of the DRG region could produce 'unlocking' of the respiratory rhythm from that of the respiratory pump. At other sites in this region, focal cooling could selectively block the effects of the inspiration-facilitating reflex induced by deflation without blocking the inspiration-inhibiting Hering-Breuer reflex. Unilateral focal cold blocks in the region of the intermediate part of the ventral respiratory group of neurons, VRG, generally caused depression of the rate of rise of inspiratory activity, but almost never apneustic effects. All effects of unilateral focal cooling both in the DRG and VRG were bilaterally symmetrical. No systematic differences between the effects on phrenic and external intercostal inspiratory activity were found in response to focal cooling either of the DRG or VRG suggesting that differential control of phrenic and external intercostal motoneurons is not exerted mainly at the level of these medullary structures. The results suggest that the DRG and VRG areas exert somewhat different effects on the respiratory pattern: DRG appears to be more concerned with integration of vagal and other inputs contributing to the inspiratory off-switch mechanisms which, however, are not confined only to the DRG. The VRG inspiratory mechanisms, on the other hand, appear to be more involved in the gain control of the inspiratory output intensity.
- Subjects :
- Male
Apnea
Physiology
Ventral respiratory group
Partial Pressure
Intercostal Muscles
Efferent Pathways
Reflex
medicine
Animals
Motor Neurons
Neurons
Nucleus ambiguus
Medulla Oblongata
Hering–Breuer reflex
business.industry
Respiration
Solitary nucleus
Vagus Nerve
Anatomy
Thorax
Respiration, Artificial
Cold Temperature
Phrenic Nerve
Spinal Nerves
medicine.anatomical_structure
nervous system
Control of respiration
Dorsal respiratory group
Anesthesia
Cats
Medulla oblongata
Female
business
Subjects
Details
- ISSN :
- 1365201X and 00016772
- Volume :
- 124
- Database :
- OpenAIRE
- Journal :
- Acta Physiologica Scandinavica
- Accession number :
- edsair.doi.dedup.....1466418a7744067420ec940000b61526
- Full Text :
- https://doi.org/10.1111/j.1748-1716.1985.tb07667.x