Biomaterial Database

Effect of inactivation of carotid sinus nerve by cold block on phrenic nerve activity in cats. 1985

S Kuwana, and T Natsui

The effect of the elimination of input via the carotid chemoreceptor on respiratory output was examined quantitatively in anesthetized, vagotomized, and paralyzed cats. The integrated phrenic nerve activity (PNA) was recorded as an indication of output of the respiratory center. Also, the elimination of the carotid chemoreflex drive was repeatedly done by a cold block of the carotid sinus nerve at various PCO2 levels during hyperoxia, normoxia, and hypoxia. The blockade induced a reduction in PNA at each PCO2 level in every PO2 group. If the highest PNA value recorded at a high PCO2 in each PO2 condition was assigned a value of 100%, the reduction of the PNA by the blockade, i.e., the respiratory effect of the carotid chemoreflex drive, would be slightly larger during normoxia (16%) than during hyperoxia (8.7%), but would be independent of PCO2. During hypoxia, this chemoreflex effect was about 40% of a low PCO2, and decreased with increments of PCO2, finally reaching about 20% of a high PCO2 level. Furthermore, the relative contribution of the carotid chemoreceptor to respiratory output, expressed as the ratio of the PNA reduction during blockade to the PNA before blockade, was inversely proportional to both PO2 and PCO2. It is concluded that the interaction of the peripheral and central chemoreceptor drive is hypoadditive at moderate and high PCO2 levels in anesthetized cats, and this interaction is emphasized by central hypoxia.

UI	MeSH Term	Description	Entries
D010791	Phrenic Nerve	The motor nerve of the diaphragm. The phrenic nerve fibers originate in the cervical spinal column (mostly C4) and travel through the cervical plexus to the diaphragm.	Nerve, Phrenic,Nerves, Phrenic,Phrenic Nerves
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing
D002346	Carotid Sinus	The dilated portion of the common carotid artery at its bifurcation into external and internal carotids. It contains baroreceptors which, when stimulated, cause slowing of the heart, vasodilatation, and a fall in blood pressure.	Sinus, Carotid
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D002628	Chemoreceptor Cells	Cells specialized to detect chemical substances and relay that information centrally in the nervous system. Chemoreceptor cells may monitor external stimuli, as in TASTE and OLFACTION, or internal stimuli, such as the concentrations of OXYGEN and CARBON DIOXIDE in the blood.	Chemoreceptive Cells,Cell, Chemoreceptive,Cell, Chemoreceptor,Cells, Chemoreceptive,Cells, Chemoreceptor,Chemoreceptive Cell,Chemoreceptor Cell
D003080	Cold Temperature	An absence of warmth or heat or a temperature notably below an accustomed norm.	Cold,Cold Temperatures,Temperature, Cold,Temperatures, Cold
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D000860	Hypoxia	Sub-optimal OXYGEN levels in the ambient air of living organisms.	Anoxia,Oxygen Deficiency,Anoxemia,Deficiency, Oxygen,Hypoxemia,Deficiencies, Oxygen,Oxygen Deficiencies