Biomaterial Database

Influence of extreme hypercapnia on respiratory motor nerve activity in cats. 1987

D Bartlett, and S L Knuth, and D K Ward

Department of Physiology, Dartmouth Medical School, Hanover, NH 03756.

Sedative drugs have been found to depress the respiratory activity of upper airway muscles more than that of the diaphragm. To determine whether CO2 at narcotic levels has a similar action, we recorded phrenic and hypoglossal nerve activities in decerebrate, vagotomized, paralyzed cats. T5 or T6 external intercostal nerve activity was also recorded in some animals. End-tidal CO2 concentration was raised progressively to over 30% or until depression of nerve activity was apparent. Respiratory frequency was reduced by severe hypercapnia in most cats. Hypoglossal nerve activity was consistently decreased more than that of the phrenic nerve. In most cases intercostal nerve activity was also more susceptible than phrenic nerve activity to hypercapnic depression. The results indicate that CO2 at narcotic levels interferes both with the central pattern generator for breathing movements and with the expression of the pattern in specific motor nerves.

UI	MeSH Term	Description	Entries
D007002	Hypoglossal Nerve	The 12th cranial nerve. The hypoglossal nerve originates in the hypoglossal nucleus of the medulla and supplies motor innervation to all of the muscles of the tongue except the palatoglossus (which is supplied by the vagus). This nerve also contains proprioceptive afferents from the tongue muscles.	Cranial Nerve XII,Twelfth Cranial Nerve,Nerve XII,Nervus Hypoglossus,Cranial Nerve XIIs,Cranial Nerve, Twelfth,Cranial Nerves, Twelfth,Hypoglossal Nerves,Hypoglossus, Nervus,Nerve XII, Cranial,Nerve XIIs,Nerve XIIs, Cranial,Nerve, Hypoglossal,Nerve, Twelfth Cranial,Nerves, Hypoglossal,Nerves, Twelfth Cranial,Twelfth Cranial Nerves,XII, Nerve,XIIs, Nerve
D007367	Intercostal Nerves	The ventral rami of the thoracic nerves from segments T1 through T11. The intercostal nerves supply motor and sensory innervation to the thorax and abdomen. The skin and muscles supplied by a given pair are called, respectively, a dermatome and a myotome.	Intercostal Nerve,Nerve, Intercostal,Nerves, Intercostal
D008297	Male		Males
D010243	Paralysis	A general term most often used to describe severe or complete loss of muscle strength due to motor system disease from the level of the cerebral cortex to the muscle fiber. This term may also occasionally refer to a loss of sensory function. (From Adams et al., Principles of Neurology, 6th ed, p45)	Palsy,Plegia,Todd Paralysis,Todd's Paralysis,Palsies,Paralyses,Paralysis, Todd,Paralysis, Todd's,Plegias,Todds Paralysis
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
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
D003655	Decerebrate State	A condition characterized by abnormal posturing of the limbs that is associated with injury to the brainstem. This may occur as a clinical manifestation or induced experimentally in animals. The extensor reflexes are exaggerated leading to rigid extension of the limbs accompanied by hyperreflexia and opisthotonus. This condition is usually caused by lesions which occur in the region of the brainstem that lies between the red nuclei and the vestibular nuclei. In contrast, decorticate rigidity is characterized by flexion of the elbows and wrists with extension of the legs and feet. The causative lesion for this condition is located above the red nuclei and usually consists of diffuse cerebral damage. (From Adams et al., Principles of Neurology, 6th ed, p358)	Decerebrate Posturing,Decorticate Rigidity,Decorticate State,Rigidity, Decerebrate,Rigidity, Decorticate,Decerebrate Posturings,Decerebrate Rigidity,Decerebrate States,Decorticate Rigidities,Decorticate States,Posturing, Decerebrate,Posturings, Decerebrate,Rigidities, Decorticate,State, Decerebrate,States, Decerebrate
D005260	Female		Females
D006935	Hypercapnia	A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.