Medium-frequency oscillations dominate the inspiratory nerve discharge of anesthetized newborn rats

Kocsis, Bernát; Gyimesi-Pelczer, Katalin; Vertes, Robert P.

doi:10.1016/s0006-8993(98)01302-x

Cited by 11 publications

(12 citation statements)

References 30 publications

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“…A more important factor may be the development with age of neural connectivity, which would facilitate interactions between I neurons and thus promotion of HFOs. This hypothesis is supported by the observation that in the neonatal anesthetized rat, autospectral frequencies (but not coherences) in the 20-to 40-Hz range are found, with no rhythms in higher frequency ranges being found (24).…”

Section: Comparison Between In Vivo and In Vitro Preparationsmentioning

confidence: 72%

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Respiratory cycle timing and fast inspiratory discharge rhythms in the adult decerebrate rat

Marchenko

Granata

Cohen

2002

American Journal of Physiology-Regulatory, Integrative and Comp

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Marchenko, Vitaliy, Antonio R. Granata, and Morton I. Cohen. Respiratory cycle timing and fast inspiratory discharge rhythms in the adult decerebrate rat. Am J Physiol Regul Integr Comp Physiol 283: R931-R940, 2002. First published June 27, 2002 10.1152/ajpregu.00117.2002In supracollicular decerebrate paralyzed adult rats, neural respiration was monitored by bilateral phrenic recordings. In the study of respiratory cycle timing, the effects of vagal afferent input (lung inflation) on respiratory phase durations resembled those seen in decerebrate cats. 1) Withholding lung inflation during neural inspiration (I) produced lengthening of I phase duration by 46% (mean, n ϭ 11). 2) Maintaining lung inflation during neural expiration (E) produced lengthening of E phase duration by 112% (mean, n ϭ 4). In the study of fast rhythms in inspiratory discharges, phrenic nerve autospectra and bilateral (left-right) phrenic coherences in 16 rats revealed two types of fast rhythm: 1) highfrequency oscillation (HFO), which had significant coherence peaks (n ϭ 9, range 106-160 Hz, mean 132 Hz); and 2) medium-frequency oscillation (MFO), which had autospectral peaks but no distinct coherence peaks (n ϭ 11, range 46-96 Hz, mean 66 Hz). These rhythms resembled MFOs and HFOs in the decerebrate cat, but the modal frequency range was about twice as large. In addition, these frequency values differed markedly from the 20-40 Hz of the rhythms found in earlier studies in neonatal in vitro preparations; the difference may be due to developmental immaturity. phrenic; vagal afferents; high-frequency oscillations; medium-frequency oscillations; spectral analysis IN RECENT YEARS, much of the research on neurogenesis of respiratory rhythm has been performed on in vitro preparations (most commonly obtained from neonatal rats), such as the en bloc (isolated brain stem-spinal cord) preparation and the medullary slice preparation (1). To help interpret observations made in vitro, it would be useful to make comparisons with in vivo observations. Although the major portion of earlier in vivo studies had been done in the cat (3, 32, 36), a number of in vivo studies have also been done in the rat (14,15,34,(41)(42)(43) and therefore might furnish suitable comparisons.The present paper deals with aspects of two broad areas of interest in both in vitro and in vivo studies: 1) the temporal structure of the overall respiratory cycle, such as the durations of the inspiration (I) and expiration (E) phases; and 2) the short-term timing relations between different inspiratory (phrenic) neural activities, as indicated by fast rhythms in their discharges.With respect to respiratory cycle timing, publications from one laboratory have reported the effects of lung afferent input (inflations) on respiratory cycle timing in the en bloc preparation with lungs attached: inflations delivered during the E phase produce prolongation of that phase (27), whereas inflations delivered during the I phase result in shortening of that phase (28,29). In previous in vivo studies...

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Section: Comparison Between In Vivo and In Vitro Preparationsmentioning

confidence: 72%

“…In two other studies (23,24), autospectral and coherence analysis was applied to I nerve discharges in anesthetized rats. Autospectral frequency peaks, mainly in the range 20-40 Hz, were found, but significant coherence peaks at these or higher frequencies between different nerve activities were rare.…”

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confidence: 99%

Respiratory cycle timing and fast inspiratory discharge rhythms in the adult decerebrate rat

Marchenko

Granata

Cohen

2002

American Journal of Physiology-Regulatory, Integrative and Comp

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“…(Nakamura et al 1999;Jean, 2001;Ballanyi, 2004). As far as respiratory rhythms transmitted to the hypoglossal nucleus are concerned, in the adult as well as neonate rat in vivo, inspiratory discharges occur at about 1-2 Hz (Thomas & Marshall, 1997) with superimposed much faster oscillations, whose frequency increases during development (Kocsis et al 1999;Marchenko et al 2002). Pioneer work by Suzue (1984) has demonstrated that isolated brainstem preparations retain rhythmic activities although at lower frequency probably because of the different experimental conditions (including the use of ambient temperature and severance of peripheral afferents).…”

Section: Functional Implicationsmentioning

confidence: 99%

Metabotropic glutamate receptor activity induces a novel oscillatory pattern in neonatal rat hypoglossal motoneurones

Sharifullina

Ostroumov

Nistri

2005

The Journal of Physiology

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Tongue muscles innervated by the hypoglossal nerves play a crucial role to ensure airway patency and milk suckling in the neonate. Using a slice preparation of the neonatal rat brain, we investigated the electrophysiological characteristics of hypoglossal motoneurones in the attempt to identify certain properties potentially capable of synchronizing motor commands to the tongue. Bath-applied DHPG, a selective agonist of group I metabotropic glutamate receptors (mGluRs), generated persistent, regular electrical oscillations (4-8 Hz) recorded from patch-clamped motoneurones. Under voltage clamp, oscillations were biphasic events, comprising large outward slow currents alternated with fast, repeated inward currents. Electrical oscillations had amplitude and period insensitive to cell membrane potential, and required intact glutamatergic transmission via AMPA receptors. Oscillations were mediated by subtype 1 receptors of group I mGluRs (mGluR1s), and were routinely observed during pharmacological block of glycinergic and GABAergic inhibition, although they could also be recorded in standard saline. Simultaneous recordings from pairs of motoneurones within the same hypoglossal nucleus demonstrated that oscillations were due to their strong electrical coupling and were blocked by the gap junction blocker carbenoxolone. Pacing of slow oscillations apparently depended on the operation of K ATP channels in view of the block by tolbutamide or glibenclamide. Under current clamp, oscillations generated more regular spike firing of motoneurones and facilitated glutamatergic excitatory inputs. These data suggest that neonatal motoneurones of the nucleus hypoglossus possess a formerly undisclosed ability to express synchronous electrical oscillations, unveiled by activation of mGluR1s.

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“…One study (9) reported that rats 14 -36 days of age produce only MFO (defined as Ͻ50 Hz) and not HFO (Ͼ50 Hz), although barbiturate anesthesia, known to depress HFO (7,18), was used. Also, this study (9) assumed that fast oscillations in rat Ph would be in the same frequency bands as for other (larger) species, an assumption that now appears invalid (13,14). The results of Tarasiuk and Sica (28), obtained by using an in vitro brain stem-spinal cord preparation, also suggested that HFO is absent in neonates.…”

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confidence: 99%

Temperature and state dependence of dynamic phrenic oscillations in the decerebrate juvenile rat

Marchenko

Rogers²

2007

American Journal of Physiology-Regulatory, Integrative and Comp

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The aim of the present study was to determine characteristics of fast oscillations in the juvenile rat phrenic nerve (Ph) and to establish their temperature and state dependence. Two different age-matched decerebrate, baro- and chemodenervated rat preparations, in vivo and in situ arterially perfused models, were used to examine three systemic properties: 1) generation and dynamics of fast oscillations in Ph activity (both preparations), 2) responses to anoxia (both preparations), and 3) the effects of temperature on fast oscillations (in situ only). Both juvenile preparations generated power and coherence in two major bands analogous to adult medium- and high-frequency oscillations (HFO) at frequencies that increased with temperature but were lower than in adults. At < 28 degrees C, however, Ph oscillations were confined primarily to one low-frequency band (20-45 Hz). During sustained anoxia, both preparations produced stereotypical state changes from eupnea to hyperpnea to transition bursting (a behavior present only in vivo during incomplete ischemia) to gasping. Thus the juvenile rat produces a sequential pattern of responses to anoxia that are intermediate forms between those produced by neonates and those produced by adults. Time-frequency analysis determined that fast oscillations demonstrated dynamics over the course of the inspiratory burst and a state dependence similar to that of adults in vivo in which hyperpnea (and transition) bursts are associated with increases in HFO, while gasping contains no HFO. Our results confirm that both the fast oscillations in Ph activity and the coherence between Ph pairs produced by the juvenile rat are profoundly state- and temperature-dependent.

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Medium-frequency oscillations dominate the inspiratory nerve discharge of anesthetized newborn rats

Cited by 11 publications

References 30 publications

Respiratory cycle timing and fast inspiratory discharge rhythms in the adult decerebrate rat

Respiratory cycle timing and fast inspiratory discharge rhythms in the adult decerebrate rat

Metabotropic glutamate receptor activity induces a novel oscillatory pattern in neonatal rat hypoglossal motoneurones

Temperature and state dependence of dynamic phrenic oscillations in the decerebrate juvenile rat

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