Selected contribution: chronic intermittent hypoxia enhances respiratory long-term facilitation in geriatric female rats.

@article{Zabka2003SelectedCC,
  title={Selected contribution: chronic intermittent hypoxia enhances respiratory long-term facilitation in geriatric female rats.},
  author={A G Zabka and Gordon S Mitchell and E. Burt Olson and Mary Behan},
  journal={Journal of applied physiology},
  year={2003},
  volume={95 6},
  pages={
          2614-23; discussion 2604
        }
}
Age and the estrus cycle affect time-dependent respiratory responses to episodic hypoxia in female rats. Respiratory long-term facilitation (LTF) is enhanced in middle-aged vs. young female rats (72). We tested the hypothesis that phrenic and hypoglossal (XII) LTF are diminished in acyclic geriatric rats when fluctuating sex hormone levels no longer establish conditions that enhance LTF. Chronic intermittent hypoxia (CIH) enhances LTF (41); thus we further predicted that CIH would restore LTF… 
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Highly Influential Citations
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Background Citations
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Methods Citations
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46 Citations

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Ageing and gonadectomy have similar effects on hypoglossal long‐term facilitation in male Fischer rats
TLDR
Data show that serotonin‐dependent plasticity in upper airway respiratory output is similar in F344 and SD rat strains, and LTF is similarly impaired in middle‐aged and gonadectomized male rats, suggesting that gonadal hormones play an important role in modulating the capacity for neuroplasticity inupper airway motor control.
Development of ventilatory long-term facilitation is dependent on estrous cycle stage in adult female rats
Ventilatory long-term facilitation is greater in 1- vs. 2-mo-old awake rats.
TLDR
Ventilatory LTF and hypoxic ventilatory response are greater in male rats shortly before their sexual maturity and that the neonatal CIH somewhat enhances ventilatories LTF approximately 3 wk after CIH, but this enhancement does not last to adulthood.
Neonatal stress affects the aging trajectory of female rats on the endocrine, temperature, and ventilatory responses to hypoxia.
TLDR
The results show that hormonal decline decreases the HVR of control animals, while leaving that of NMS female animals unaffected, suggesting that neonatal stress alters the interaction between sex hormone regulation and the development of body temperature, hormonal, and ventilatory responses to hypoxia.
Early postnatal chronic intermittent hypoxia modifies hypoxic respiratory responses and long-term phrenic facilitation in adult rats.
TLDR
It is concluded that early postnatal CIH modifies normoxic and hypoxic ventilatory and phrenic responses that persist at 1 mo after cessation of CIH and markedly differ from previously reported increased neural plasticity changes induced by CIH in adult rats.
Differential expression of respiratory long-term facilitation among inbred rat strains
Hypoxic and hypercapnic ventilatory responses in aging male vs. aging female rats.
TLDR
Assessment of the effects of sex and age on the hypoxic (HVR) and the hypercapnic ventilatory responses (HCVR) of awake rats relative to systemic hormone levels found no age-related changes in the HVR or HCVR.
Daily intermittent hypoxia augments spinal BDNF levels, ERK phosphorylation and respiratory long-term facilitation
Conversion from testosterone to oestradiol is required to modulate respiratory long‐term facilitation in male rats
TLDR
It is concluded that the conversion of testosterone to oestradiol modulates phrenic and XII LTF in male F344 rats.
Experimental protocols and preparations to study respiratory long term facilitation
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References

SHOWING 1-10 OF 77 REFERENCES
Selected contribution: Time-dependent hypoxic respiratory responses in female rats are influenced by age and by the estrus cycle.
TLDR
Testing the hypotheses that the short-term hypoxic response (STHR), posthypoxia frequency decline (PHFD) and LTF of phrenic and hypoglossal (XII) motor output change with age and stage of the estrus cycle in female rats found that these responses increased with age.
Long term facilitation of respiratory motor output decreases with age in male rats
1 Long term facilitation (LTF) is a serotonin‐dependent augmentation of respiratory motor output (phrenic and hypoglossal) following episodic hypoxia. Since ageing influences respiratory control…
Life‐long impairment of hypoxic phrenic responses in rats following 1 month of developmental hyperoxia
TLDR
It is concluded that exposure to hyperoxia for the first month of life causes life‐long impairment of carotid chemoreceptor function and, consequently, blunted phrenic responses to hypoxia.
Hypoxia-induced long-term facilitation of respiratory activity is serotonin dependent.
Chronic Intermittent Hypoxia Elicits Serotonin-Dependent Plasticity in the Central Neural Control of Breathing
TLDR
It is suggested that CIH elicits unique forms of serotonin-dependent plasticity in the central neural control of breathing and enhanced LTF after CIH may involve an upregulation of a non-5-HT2 serotonin receptor subtype or subtypes.
Episodic but not continuous hypoxia elicits long‐term facilitation of phrenic motor output in rats
TLDR
The results indicate that hypoxia‐induced long‐term facilitation of phrenic motor output is sensitive to the pattern of hypoxic exposure in anaesthetized rats.
Reactive oxygen species in the plasticity of respiratory behavior elicited by chronic intermittent hypoxia.
TLDR
It is demonstrated that acute, brief EH elicits LTF in respiratory motor output and prior conditioning with CIH, but not with comparable, cumulative duration of sustained hypoxia, augments LTF elicited by acute EH; and O(2)(-)* radical scavenger prevents CIH-induced potentiation of LTF of respiration.
Expression of hypoglossal long-term facilitation differs between substrains of Sprague-Dawley rat.
TLDR
It is concluded that the expression of hypoglossal LTF differs between SD rat substrains, indicating a difference in their genetic predisposition to neural plasticity.
Invited review: Intermittent hypoxia and respiratory plasticity.
TLDR
The working hypothesis is that increased brain-derived neurotrophic factor enhances glutamatergic synaptic currents in phrenic motoneurons, increasing their responsiveness to bulbospinal inspiratory inputs and reflecting a general mechanism whereby intermittent serotonin receptor activation elicits respiratory plasticity, adapting system performance to the ever-changing requirements of life.
Phrenic long-term facilitation requires 5-HT receptor activation during but not following episodic hypoxia.
TLDR
It is concluded that 5-HT receptor activation is necessary to initiate (during hypoxia) but not maintain (following hypoxIA) phrenic LTF.
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