Biomaterial Database

I. Pulmonary-CO2 ventilatory reflex in dogs: effective range of CO2 and results of vagal cooling. 1978

R B Banzett, and H M Coleridge, and J C Coleridge

Bartoli et al. (1974) found in dogs with constant PaCO2 that an increase in PCO2 in the vascularly isolated lungs increased ventilatory drive by a vagal reflex. We have examined the range of lung PCO2 over which the reflex operates. In anaesthetized dogs we ventilated the lungs separately with O2, maintaining gas exchange with the right lung. When we occluded the left pulmonary artery, left lung PCO2 fell to 2--4 mm Hg, and phrenic nerve firing decreased significantly. Phrenic activity increased again when left lung PCO2 was raised in steps to 19, 32 and finally to 50 mm Hg. PaCO2 was unchanged. Phrenic responses were abolished by cutting the left vagus nerve or by cooling it to 7--8 degrees C. The largest increase in phrenic activity occurred when left lung PCO2 was increased from 2 to 19 mm Hg, and the smallest when PCO2 was raised from 32 to 50 mm Hg. Hence the significance of the pulmonary-CO2 ventilatory reflex may lie in depression of ventilatory drive when pulmonary CO2 falls below normal, rather than in stimulation of breathing when pulmonary CO2 increases above normal.

UI	MeSH Term	Description	Entries
D008168	Lung	Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.	Lungs
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
D012018	Reflex	An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
D002245	Carbon Dioxide	A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.	Carbonic Anhydride,Anhydride, Carbonic,Dioxide, Carbon
D003080	Cold Temperature	An absence of warmth or heat or a temperature notably below an accustomed norm.	Cold,Cold Temperatures,Temperature, Cold,Temperatures, Cold
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
D000344	Afferent Pathways	Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.	Afferent Pathway,Pathway, Afferent,Pathways, Afferent
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
D014630	Vagus Nerve	The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx).	Cranial Nerve X,Pneumogastric Nerve,Tenth Cranial Nerve,Nerve X,Nervus Vagus,Cranial Nerve, Tenth,Cranial Nerves, Tenth,Nerve X, Cranial,Nerve Xs,Nerve, Pneumogastric,Nerve, Tenth Cranial,Nerve, Vagus,Nerves, Pneumogastric,Nerves, Tenth Cranial,Nerves, Vagus,Pneumogastric Nerves,Tenth Cranial Nerves,Vagus Nerves,Vagus, Nervus