Thermal responses of carotid body cells

Baron, Margarita; Eyzaguirre, C.

doi:10.1002/neu.480060507

Cited by 12 publications

(3 citation statements)

References 7 publications

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“…These include various circulating hormones including catecholamines (537, 553), but see (534), angiotensin (30, 296, 413, 506, 521), adenosine (573, 759, 852), and extracellular ions, particularly K + (54, 412, 533) as well as changes in osmolarity (136, 300, 301, 590) and temperature (26, 61, 62, 69, 572). The carotid body responses to these stimuli are robust and reproducible and can in most cases also be observable at the level of cardiorespiratory reflexes (602, 672, 777, 942), which has led to the notion that the carotid body might act as a polymodal receptor within the stress axis of the body (478).…”

Section: Other Physiological Stimuli Of the Carotid Bodymentioning

confidence: 99%

Peripheral Chemoreceptors: Function and Plasticity of the Carotid Body

Kumar

Prabhakar

2012

Comprehensive Physiology

458

572

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The discovery of the sensory nature of the carotid body dates back to the beginning of the 20th century. Following these seminal discoveries, research into carotid body mechanisms moved forward progressively through the 20th century, with many descriptions of the ultrastructure of the organ and stimulus-response measurements at the level of the whole organ. The later part of 20th century witnessed the first descriptions of the cellular responses and electrophysiology of isolated and cultured type I and type II cells, and there now exist a number of testable hypotheses of chemotransduction. The goal of this article is to provide a comprehensive review of current concepts on sensory transduction and transmission of the hypoxic stimulus at the carotid body with an emphasis on integrating cellular mechanisms with the whole organ responses and highlighting the gaps or discrepancies in our knowledge. It is increasingly evident that in addition to hypoxia, the carotid body responds to a wide variety of blood-borne stimuli, including reduced glucose and immune-related cytokines and we therefore also consider the evidence for a polymodal function of the carotid body and its implications. It is clear that the sensory function of the carotid body exhibits considerable plasticity in response to the chronic perturbations in environmental O2 that is associated with many physiological and pathological conditions. The mechanisms and consequences of carotid body plasticity in health and disease are discussed in the final sections of this article.

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Section: Other Physiological Stimuli Of the Carotid Bodymentioning

confidence: 99%

Peripheral Chemoreceptors: Function and Plasticity of the Carotid Body

Kumar

Prabhakar

2012

Comprehensive Physiology

458

572

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“…Receptor depolarization induced by high temperature was probably produced mainly by a direct effect on the nerve endings. In fact, the glomus type I cells are depolarized by cold and hyperpolarized at higher temperature (Baron and Eyzaguirre, 1975; see also Eyzaguirre, Fidone, and Nishi,…”

Section: Effects Of Temperaturementioning

confidence: 97%

Effects of different ions on resting polarization and on the mass receptor potential of carotid body chemosensors

Eyzaguirre

Nishi

1976

J. Neurobiol.

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The carotid body and its own nerve were removed from cats anesthetized with sodium pentobarbital and placed in an air gap system; the carotid body was bathed in modified Locke's solution equilibrated with 50% O2 in N2, pH 7.43 at 35 degrees C. The sensory discharges, changes in "resting" receptor polarization and the mass receptor potential evoked by ACh or NaCN were recorded with nonpolarizable electrodes placed across the gap. Receptor potentials and sensory discharges evoked by ACh showed an appreciable increase in amplitude and frequency when the preparation was bathed in eserinized Locke. Eserine did not change appreciably the responses evoked by NaCN. Excessive depolarization elicited by either ACh or NaCN was accompanied by sensory discharge block. Removal of K+ ions from the bathing solution induced receptor hyperpolarization and an increase in the amplitude of the evoked receptor potentials. An increase of K+ concentration had the opposite effect. Reduction of Na+ or NaCl to one half, or total removal of this salt, induced an initial reduction and later disappearance of the sensory discharges, some receptor hyperpolarization and a reduction in the amplitude of the evoked receptor potential. Reduction or removal of Ca++ produced receptor depolarization, a marked depression of the evoked receptor potentials, an increase in the frequency of the sensory discharges and a reduction in the amplitude of the nerve action potentials. High Ca++ or Mg++ had little or no effect on action potential amplitude or resting polarization, but decreased sensory discharge frequency and the evoked receptor potentials. Total or partial replacement of Ca++ with Mg++ induced complex effects: (1) receptor depolarization which occurred in low Ca++, was prevented by addition of Mg++ ions; (2) the amplitude of the evoked receptor potentials was depressed; (3) the nerve discharge frequency was reduced as it was in high Mg++ solutions; and (4) the amplitude of the nerve action potentials was reduced as it was in low Ca++ solutions. Temperature had a marked effect on the chemoreceptors since at high temperatures the receptors were depolarized and the discharge frequency increased. The baseline discharge and responses evoked by ACh or NaCN were depressed at low temperatures. The results are discussed in terms of possible receptor mechanisms influenced by the different ions.

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“…Carotid bodies were removed from adult New Zealand rabbits and quickly cleaned of surrounding connective tissue in a chamber filled with an oxygenated modified Tyrode's solution [3] : in raM, NaCI, 111.23; Na-glutamate, 41.99; KC1, 4.69; CaC12, 2.16; MgCI2, 0.49; Hepes, 4.99; HC1, 2--4; glucose, 5.5. The tissue was then transferred for preincubation to oxygenated Tyrode's at 37°C containing 40 ~m [3H]tyrosine (2 Ci/mM; Amersham), 1 mM ascorbic acid and 100 ~M 6-methyltetrahydrobiopterin (Calbiochem).…”

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confidence: 99%

Increased release of [3H]dopamine during low O2 stimulation of rabbit carotid body in vitro

González

Fidone

1977

Neuroscience Letters

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SUMMARYRabbit carotid bodies synthesized [3H]dopamine (DA) during a 3-h incubation period in modified Tyrode's solution containing 40 uM [3H]tyrosine. Following tbis loading period, the carotid bodies were exposed for one additional hour to unlabelled Tyrode's solution equilibrated with either 10% oxygen in nitrogen or with 100% oxygen. The carotid bodies exposed to low O2 released 81% more [3H]dopamine during this one-hour period than the carotid bodies exposed only to pure oxygen. These data suggest that hypoxia induces release of DA from the carotid body.It is now well documented that the mammalian carotid body contains the biogenic amines dopamine, norepinephrine and 5-hydroxytryptamine [9,12,29], and that of these, dopamine (DA) is present in the tissue in the highest concentration [12,15]. ~ere is also convincing evidence that these substances are contained primarily within the glomus, or Type I, cells of the carotid body [6,7]. Electrophysiological and pharmacological studies in the cat [23,24,28], dog [4] and rabbit (Monti-Bloch and Eyzaguirre, pets. comm.) have shown that exogenous DA alters chemoreceptor activity recorded from the carotid nerve, and it has been suggested that during natural stimulation of the carotid body release of endogenous DA from the glomus cells may function to modulate the activity of chemoreceptor nerve fibers which terminate upon these cells [2,14,28]. However, previous studies of the effects of natural stimulation on the DA stores of the carotid body have produced conflicting results, and there are no ~tudies which have attempted to directly demonstrate either increased release or tunlover of carotid body DA during natttral stimu]a-

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Thermal responses of carotid body cells

Cited by 12 publications

References 7 publications

Peripheral Chemoreceptors: Function and Plasticity of the Carotid Body

Peripheral Chemoreceptors: Function and Plasticity of the Carotid Body

Effects of different ions on resting polarization and on the mass receptor potential of carotid body chemosensors

Increased release of [3H]dopamine during low O2 stimulation of rabbit carotid body in vitro

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