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Interactions Between Postnatal Sustained Hypoxia and Intermittent Hypoxia in the Adulthood to Alter Brainstem Structures and Respiratory Function

  • Elena Olea
  • Susana P. Gaytan
  • Ana Obeso
  • Constancio Gonzalez
  • Rosario PasaroEmail author
Conference paper
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 758)

Abstract

Neural plasticity is defined as a persistent change in the morphology and/or function based on prior experiences. Plasticity is well evident when the triggering experience occurs early in life, but in the case of respiratory control plasticity, it also can be triggered in adult life. We have combined a 10 days postnatal hypoxic (PH) (0–10 days of age;11% O2) and a 15 days intermittent hypoxia (IH) exposures in the adulthood (90–105 days of age; 5% O2, 40 s/20% O2, 80 s; 8 h/day) to test if early PH interacts with IH of the adulthood to generate detrimental plastic changes. After recording of ventilatory parameters, the brains were studied immunocytochemically for localization of the organization pattern of non-phosphorylated subunit of neurofilament H (NFH) and tyrosine hydroxylase (TH) expression in the nucleus tractus solitarius (Sol) and caudal (CVL) and rostral ventrolateral reticular (RVL) nuclei, areas related to central cardio-respiratory regulation. In comparison to control, PH male rats (but not females) at 1 month of age hyperventilated at rest, in response to moderate hypoxia (12% O2) and 5% CO2, the effect being due to increased tidal volume. At 3.5 months sex differences in ventilation disappeared and it was indistinguishable between control and PH. IH tended to decrease ventilation in both control (C) and PH animals. PH augmented PENH values in air and in hypoxic conditions when compared with C group. IH in both groups, tended to decrease the PENH value, being statistically different in PH+IH. Results also show an increment of disorganization of NFH-positive labeled structures at the level of Sol and CVL/RVL nuclei in PH, IH and HP+HI groups. PH rats showed differences in the number of TH-positive neurons at the level of CVL/RVL nuclei, which was increased in the PH and PH+IH groups with respect to C one. In conclusion, PH alters the central morpho-physiological organization and the catecholaminergic components of cardio-respiratory nuclei, whose effects were enhanced after a period of IH in the adulthood.

Keywords

Neural plasticity Nucleus tractus solitarius Caudal ventrolateral reticular nucleus Rostral ventrolateral reticular nucleus Respiratory control plasticity Carotid body chemoreflex 

Notes

Acknowledgements

Supported by Grants BFU2007-61848 (DGICYT), CIBER CB06/06/0050 (ISCiii), and P08-CVI-03934 and P09-CVI-4617 (Junta de Andalucía). Thanks to the technical assistance of Mª Angeles Bueso and Elena Gonzalez.

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Copyright information

© Springer Science+Business Media Dordrecht 2012

Authors and Affiliations

  • Elena Olea
    • 1
  • Susana P. Gaytan
    • 2
  • Ana Obeso
    • 1
  • Constancio Gonzalez
    • 1
  • Rosario Pasaro
    • 2
    Email author
  1. 1.Department of Biochemistry and Molecular Biology and Physiology and IBGMCIBERES-Institute Carlos III, University of Valladolid School of Medicine and CSICValladolidSpain
  2. 2.Department of Physiology and ZoologyUniversity of SevilleSevilleSpain

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