Biomaterial Database

Influence of intralaryngeal CO2 on the response of laryngeal afferents to upper airway negative pressure. 1994

T K Ghosh, and O P Mathew

Department of Pediatrics, East Carolina School of Medicine, Greenville, North Carolina 27858.

Effects of intralaryngeal CO2 on the response of superior laryngeal afferents to negative pressure were investigated in 20 anesthetized spontaneously breathing adult cats. Single-fiber action potentials were recorded from the peripheral cut end of the superior laryngeal nerve. The larynx was exposed to negative pressure during inspiration when the animal breathed against an occluded upper airway. Among the 99 receptors evaluated, 54 were respiratory modulated and 45 were nonmodulated endings. The effect of intralaryngeal CO2 on the response of 39 receptors responding to negative pressure was determined by exposure of the larynx to CO2 or air for 1 min followed immediately by upper airway occlusion. The mean discharge frequency of 22 fibers inhibited by negative pressure was 32.4 +/- 2.6 Hz during air trials compared with 29.9 +/- 2.6 Hz during CO2 trials (P < 0.005). During occlusion of the upper airway after the warm humidified air trial, the discharge frequency of these endings decreased to 24.2 +/- 2.3 Hz compared with 17.5 +/- 2.2 Hz after CO2 trial (P < 0.001). The mean discharge frequencies of 17 fibers stimulated by negative pressure were 3.7 +/- 2.6 and 4.4 +/- 1.8 Hz, respectively, during air and CO2 trials. The mean frequencies increased to 14.7 +/- 3.5 Hz (air) and 18.6 +/- 4.0 Hz (CO2) during upper airway occlusions (P < 0.01). We conclude that intralaryngeal CO2 can alter the response of pressure-sensitive laryngeal afferents, thereby having a role in the maintenance of upper airway patency.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D007823	Laryngeal Nerves	Branches of the VAGUS NERVE. The superior laryngeal nerves originate near the nodose ganglion and separate into external branches, which supply motor fibers to the cricothyroid muscles, and internal branches, which carry sensory fibers. The RECURRENT LARYNGEAL NERVE originates more caudally and carries efferents to all muscles of the larynx except the cricothyroid. The laryngeal nerves and their various branches also carry sensory and autonomic fibers to the laryngeal, pharyngeal, tracheal, and cardiac regions.	Laryngeal Nerve, Superior,Laryngeal Nerve,Laryngeal Nerves, Superior,Nerve, Laryngeal,Nerve, Superior Laryngeal,Nerves, Laryngeal,Nerves, Superior Laryngeal,Superior Laryngeal Nerve,Superior Laryngeal Nerves
D008297	Male		Males
D008465	Mechanoreceptors	Cells specialized to transduce mechanical stimuli and relay that information centrally in the nervous system. Mechanoreceptor cells include the INNER EAR hair cells, which mediate hearing and balance, and the various somatosensory receptors, often with non-neural accessory structures.	Golgi Tendon Organ,Golgi Tendon Organs,Krause's End Bulb,Krause's End Bulbs,Mechanoreceptor,Mechanoreceptor Cell,Meissner's Corpuscle,Neurotendinous Spindle,Neurotendinous Spindles,Receptors, Stretch,Ruffini's Corpuscle,Ruffini's Corpuscles,Stretch Receptor,Stretch Receptors,Mechanoreceptor Cells,Bulb, Krause's End,Bulbs, Krause's End,Cell, Mechanoreceptor,Cells, Mechanoreceptor,Corpuscle, Meissner's,Corpuscle, Ruffini's,Corpuscles, Ruffini's,End Bulb, Krause's,End Bulbs, Krause's,Krause End Bulb,Krause End Bulbs,Krauses End Bulb,Krauses End Bulbs,Meissner Corpuscle,Meissners Corpuscle,Organ, Golgi Tendon,Organs, Golgi Tendon,Receptor, Stretch,Ruffini Corpuscle,Ruffini Corpuscles,Ruffinis Corpuscle,Ruffinis Corpuscles,Spindle, Neurotendinous,Spindles, Neurotendinous,Tendon Organ, Golgi,Tendon Organs, Golgi
D009412	Nerve Fibers	Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.	Cerebellar Mossy Fibers,Mossy Fibers, Cerebellar,Cerebellar Mossy Fiber,Mossy Fiber, Cerebellar,Nerve Fiber
D009475	Neurons, Afferent	Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.	Afferent Neurons,Afferent Neuron,Neuron, Afferent
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
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
D005260	Female		Females
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