Localization of the medullary respiratory neurons in rats by microelectrode recording

Howard, B.R.; Tabatabai, M.

doi:10.1152/jappl.1975.39.5.812

Cited by 29 publications

(4 citation statements)

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“…Since the phrenic nerve activity was not recorded in these experiments, we are not in a position to relate these neurons clearly to the generation or transmission of central respiratory activity. However, the present results are consistent with this idea, as demonstrated by others using extracellular recording techniques (Howard and Tabatabai, 1975). The average of the neuronal membrane potentials triggered by arterial pressure pulse was flat in these RVLM neurons (Fig.…”

Section: Recording From Noncardiovascular Neuronssupporting

confidence: 94%

Intracellular analysis in vivo of different barosensitive bulbospinal neurons in the rat rostral ventrolateral medulla

Kitai

1992

J. Neurosci.

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Neurons located in the rostral ventrolateral medulla (RVLM) with projections to the intermediolateral column (IML) in the spinal cord were electrophysiologically characterized and anatomically identified using an intracellular recording technique in vivo. A group of spontaneously active neurons was antidromically activated by electrical stimulation of the IML in the thoracic spinal cord (T2-T3 level). The axonal conduction velocities ranged from 1.5 m/sec to 11.0 m/sec; mean value, 5.5 +/- 2.6 m/sec (+/- SD). The firing pattern and changes in membrane potential in relation to the cardiac cycle were investigated in these bulbospinal neurons. A first group discharged action potentials with higher frequency at the end of the diastolic/beginning of the systolic period. The average of the neuronal membrane potentials demonstrated depolarizing potentials at the end of the diastolic/beginning of the systolic period. These depolarizing potentials increased in magnitude when the neurons were hyperpolarized. Therefore, they were characterized as EPSPs. The baroreceptor reflex activation produced by the increase in systemic arterial pressure following intravenous injection of phenylephrine elicited hyperpolarization, a decrease in the rate of discharge, and an increase in the membrane input resistance, suggesting that a disfacilitatory effect was produced by the activation of baroreceptor inputs on these bulbospinal neurons. Conversely, the inactivation of the baroreceptor reflex by intravenous injection of sodium nitroprusside produced depolarization and an increase in the firing rate. These neurons were characterized as baroreceptor-sensitive type I neurons. A second group of bulbospinal neuron in the RVLM was differentiated from the first group because it demonstrated a decrease in the frequency of discharge at the end of the diastolic/beginning of the systolic period. The average of the membrane potentials showed hyperpolarizing potentials that decreased in magnitude when the neuron was hyperpolarized. These hyperpolarizing potentials occurred at the end of the diastolic/beginning of the systolic period and were reversed in polarity after intracellular injections of chloride ions for several minutes. Therefore, these potentials were characterized as chloride-dependent IPSPs locked to the cardiac cycle. In some of these neurons, the electrical stimulation of the IML produced, in addition to the antidromic action potential, a monosynaptic EPSP with a shorter latency. Based on these unique characteristics, these neurons were defined as barosensitive type II neurons. During constant baroreceptor inactivation achieved by the hypotension produced by intravenous infusions of sodium nitroprusside, the pattern of discharge of barosensitive type II neurons became very regular, and the IPSPs locked to the cardiac cycle were absent.(ABSTRACT TRUNCATED AT 400 WORDS)

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Section: Recording From Noncardiovascular Neuronssupporting

confidence: 94%

Intracellular analysis in vivo of different barosensitive bulbospinal neurons in the rat rostral ventrolateral medulla

Kitai

1992

J. Neurosci.

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“…Our quantitative EM data suggest that glycinergic terminals comprise about 30% of all synaptic terminals in the interstitial, dorso-medial/lateral and ventrolateral subnuclei, but only about 17% in the commissural and gelatinosus subnuclei. The areas of the NTS most densely innervated by glycinergic fibres do not correspond rigidly to functionally specific regions of the nucleus, but include termination sites of afferent fibres subserving cardiorespiratory functions, as identified in rodents by experiments involving neuronal tracing (Kalia and Sullivan, 1982;Housley et al, 1987;Ciriello et al, 1994) and electrophysiological recording (Howard and Tabatabai, 1975;Paton et al, 1991;Deuchars et al, 2000;Ezure et al, 2002;Kubin et al, 2006).…”

Section: Distribution Of Glycinergic Neurones In the Ntsmentioning

confidence: 99%

Co-localisation of markers for glycinergic and GABAergic neurones in rat nucleus of the solitary tract: Implications for co-transmission

Batten

Pow

Saha

2010

Journal of Chemical Neuroanatomy

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“…The first reports on the adult rat respiratory network suggested that the medullary respiratory neurons might be located in the VRG and DRG groups (202,413). The existence of the DRG has been questioned, however (118,344,491), and the results of both in vitro neonatal brain stem preparations and in vivo adult experiments have shown that it may not in fact exist in the rat (193).…”

Section: Adult Rat Medullary Networkmentioning

confidence: 99%

Maturation of the Mammalian Respiratory System

Hilaire

Duron

1999

Physiological Reviews

182

141

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In this review, the maturational changes occurring in the mammalian respiratory network from fetal to adult ages are analyzed. Most of the data presented were obtained on rodents using in vitro approaches. In gestational day 18 (E18) fetuses, this network functions but is not yet able to sustain a stable respiratory activity, and most of the neonatal modulatory processes are not yet efficient. Respiratory motoneurons undergo relatively little cell death, and even if not yet fully mature at E18, they are capable of firing sustained bursts of potentials. Endogenous serotonin exerts a potent facilitation on the network and appears to be necessary for the respiratory rhythm to be expressed. In E20 fetuses and neonates, the respiratory activity has become quite stable. Inhibitory processes are not yet necessary for respiratory rhythmogenesis, and the rostral ventrolateral medulla (RVLM) contains inspiratory bursting pacemaker neurons that seem to constitute the kernel of the network. The activity of the network depends on CO2 and pH levels, via cholinergic relays, as well as being modulated at both the RVLM and motoneuronal levels by endogenous serotonin, substance P, and catecholamine mechanisms. In adults, the inhibitory processes become more important, but the RVLM is still a crucial area. The neonatal modulatory processes are likely to continue during adulthood, but they are difficult to investigate in vivo. In conclusion, 1) serotonin, which greatly facilitates the activity of the respiratory network at all developmental ages, may at least partly define its maturation; 2) the RVLM bursting pacemaker neurons may be the kernel of the network from E20 to adulthood, but their existence and their role in vivo need to be further confirmed in both neonatal and adult mammals.

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Localization of the medullary respiratory neurons in rats by microelectrode recording

Cited by 29 publications

References 0 publications

Intracellular analysis in vivo of different barosensitive bulbospinal neurons in the rat rostral ventrolateral medulla

Intracellular analysis in vivo of different barosensitive bulbospinal neurons in the rat rostral ventrolateral medulla

Co-localisation of markers for glycinergic and GABAergic neurones in rat nucleus of the solitary tract: Implications for co-transmission

Maturation of the Mammalian Respiratory System

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