TASK1 and TASK3 Are Coexpressed With ASIC1 in the Ventrolateral Medulla and Contribute to Central Chemoreception in Rats

Intracellular pH (pHi) regulation was studied in neurons from two chemosensitive [nucleus of the solitary tract (NTS) and ventrolateral medulla (VLM)] and two nonchemosensitive [hypoglossal (Hyp) and inferior olive (IO)] areas of the medulla oblongata. Intrinsic buffering power (βint) was the same in neurons from all regions (46 mM/pH U). Na+/H+exchange mediated recovery from acidification in all neurons [Ritucci, N. A., J. B. Dean, and R. W. Putnam. Am. J. Physiol. 273 ( Regulatory Integrative Comp. Physiol.42): R433–R441, 1997]. Cl−/[Formula: see text]exchange mediated recovery from alkalinization in VLM, Hyp, and IO neurons but was absent from most NTS neurons. The Na+/H+exchanger from NTS and VLM neurons was fully inhibited when extracellular pH (pHo) <7.0, whereas the exchanger from Hyp and IO neurons was fully inhibited only when pHo <6.7. The Cl−/[Formula: see text]exchanger from VLM, but not Hyp and IO neurons, was inhibited by pHo of 7.9. These pH regulatory properties resulted in steeper pHi-pHorelationships in neurons from chemosensitive regions compared with those from nonchemosensitive regions. These differences are consistent with a role for changes of pHi as the proximate signal in central chemoreception and changes of pHo in modulating pHi changes.

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Fluorescence location of RVLM kainate microinjections that alter the control of breathing

Journal of Applied Physiology ◽

10.1152/jappl.1990.68.3.1157 ◽

1990 ◽

Vol 68 (3) ◽

pp. 1157-1166 ◽

Cited By ~ 33

Author(s):

E. E. Nattie ◽

A. H. Li

Keyword(s):

Blood Pressure ◽

Carotid Sinus ◽

Ventrolateral Medulla ◽

Related Activity ◽

Co2 Sensitivity ◽

Retrotrapezoid Nucleus ◽

Fluorescent Microbeads ◽

Carotid Sinus Nerve Stimulation ◽

Central Chemoreception ◽

Retrofacial Nucleus

Kainic acid (4.7 mM) applied to the rostral ventrolateral medulla (RVLM) surface decreases phrenic output, CO2 sensitivity, and blood pressure in chloralose-urethan-anesthetized, vagotomized, paralyzed, glomectomized, servoventilated cats. In this study using the same preparation, bilateral 50- to 100-nl kainate injections just below the RVLM surface better localized these responses topographically. The physiological responses to unilateral 10-nl kainate injections were then correlated with anatomic location determined by fluorescent microbeads (0.5 micron diam). Many sites were associated with no effect, a few rostral and caudal sites with increased phrenic activity, and cluster of sites with decreased phrenic activity often to apnea, decreased CO2 sensitivity, and decreased responses to carotid sinus nerve stimulation. Blood pressure was unaffected. These sites, within 400 microns of the surface, were ventral to the facial nucleus, ventrolateral to the nucleus paragigantocellularis lateralis, caudal to the superior olive, and rostral to the retrofacial nucleus. They appeared to be within the recently described retrotrapezoid nucleus, which contains cells with respiratory-related activity and projections to the dorsal and ventral respiratory groups. Cells within this site appear able to provide tonic input to respiration and to affect peripheral and central chemoreception.

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Role of ventrolateral medulla in regulation of respiratory and cardiovascular systems

Journal of Applied Physiology ◽

10.1152/jappl.1986.61.4.1249 ◽

1986 ◽

Vol 61 (4) ◽

pp. 1249-1263 ◽

Cited By ~ 148

Author(s):

D. E. Millhorn ◽

F. L. Eldridge

Keyword(s):

Spinal Cord ◽

Sympathetic Neurons ◽

Excitatory Input ◽

Ventrolateral Medulla ◽

Sense Organs ◽

New Findings ◽

Afferent Inputs ◽

Central Chemoreception ◽

Cardiovascular Systems

It is now widely accepted that the ventrolateral aspect of the medulla oblongata (VLM) plays an important role in regulation of the respiratory and cardiovascular systems. The VLM has been implicated as being involved in a number of different physiological functions, including central chemoreception, integration of afferent inputs from certain sense organs to the respiratory and cardiovascular controllers, the source of excitatory input to preganglionic sympathetic neurons in the spinal cord, and location of synaptic relay between the higher brain defense areas and spinal cord sympathetic elements. In recent years there have been a number of important findings concerning both the anatomical substrate and neurophysiological characteristics of VLM neurons involved in regulation of the respiratory and cardiovascular systems. New anatomical findings show that neuronal networks located in the VLM send projections to and receive projections from brain stem nuclei that have traditionally been associated with respiratory and cardiovascular regulation. Nevertheless, there are still many important questions concerning the role of the VLM in control of these vital systems that have yet to be answered. For instance, are the same VLM neurons involved in control of both systems? Is the VLM the only site for central respiratory chemoreception? This review will endeavor to examine new findings and to reexamine some older findings concerning the VLM.

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Acid-sensing ion channels are expressed in the ventrolateral medulla and contribute to central chemoreception

Scientific Reports ◽

10.1038/srep38777 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 7

Author(s):

Nana Song ◽

Ruijuan Guan ◽

Qian Jiang ◽

Comron J. Hassanzadeh ◽

Yuyang Chu ◽

...

Keyword(s):

Ion Channels ◽

Ventrolateral Medulla ◽

Acid Sensing Ion Channels ◽

Central Chemoreception

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Julius H. Comroe, Jr., Distinguished Lecture: Central chemoreception: then … and now

Journal of Applied Physiology ◽

10.1152/japplphysiol.01061.2010 ◽

2011 ◽

Vol 110 (1) ◽

pp. 1-8 ◽

Cited By ~ 51

Author(s):

Eugene Nattie

Keyword(s):

Nucleus Tractus Solitarius ◽

Locus Ceruleus ◽

Ventrolateral Medulla ◽

Output Variable ◽

American Physiological Society ◽

Retrotrapezoid Nucleus ◽

Afferent Information ◽

Central Chemoreception ◽

Primary Output ◽

Nonadditive Interaction

The 2010 Julius H. Comroe, Jr., Lecture of the American Physiological Society focuses on evolving ideas in chemoreception for CO2/pH in terms of what is “sensed,” where it is sensed, and how the sensed information is used physiologically. Chemoreception is viewed as involving neurons (and glia) at many sites within the hindbrain, including, but not limited to, the retrotrapezoid nucleus, the medullary raphe, the locus ceruleus, the nucleus tractus solitarius, the lateral hypothalamus (orexin neurons), and the caudal ventrolateral medulla. Central chemoreception also has an important nonadditive interaction with afferent information arising at the carotid body. While ventilation has been viewed as the primary output variable, it appears that airway resistance, arousal, and blood pressure can also be significantly affected. Emphasis is placed on the importance of data derived from studies performed in the absence of anesthesia.

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Effect on breathing of neuronal dysfunction in the caudal ventral medulla of goats

Journal of Applied Physiology ◽

10.1152/jappl.1995.79.5.1586 ◽

1995 ◽

Vol 79 (5) ◽

pp. 1586-1594 ◽

Cited By ~ 6

Author(s):

P. J. Ohtake ◽

H. V. Forster ◽

L. G. Pan ◽

T. F. Lowry ◽

M. J. Korducki ◽

...

Keyword(s):

Hypoglossal Nerve ◽

Control Of Breathing ◽

Inhibitory Neurons ◽

Ventrolateral Medulla ◽

Neuronal Dysfunction ◽

Inspiratory Time ◽

Caudal Ventrolateral Medulla ◽

Ventral Medulla ◽

Central Chemoreception

It has been reported that the caudal ventrolateral medulla (VLM) is important in central chemoreception and the control of breathing. The objective of this study was to determine in adult goats the effects on breathing of neuronal dysfunction of this caudal VLM region (area L; caudal to rostral hypoglossal nerve rootlet). Thermodes were chronically implanted on the VLM to cool neurons and thereby cause neuronal dysfunction. During awake and (halothane) anesthetized states, cooling the caudal VLM for 20 s to 20 degrees C did not alter breathing (P > 0.10). However, between 20 and 30 s of cooling and during recovery from cooling 0–4 mm caudal to the rostral hypoglossal rootlet, there was a 12 (awake) to 25% (anesthetized) increase (P < 0.05) in breathing. This tachypneic hyperpnea was uniform over conditions of eucapnia, hypercapnia, and hypoxia and resulted from reduced inspiratory time that increased frequency. We conclude that in goats inhibitory neurons are located in area L and the lateral caudal ventral medulla.

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