The goal of this research is to gain a better understanding of the mechanisms which coordinate the activation of the upper airway muscles with that of the diaphragm during postnatal development. Dysfunction in this system results in episodes of obstructive apneas found in premature infants and adults with obstructive sleep apnea. These experiments are designed to measure the changes in the membrane properties of the respiratory motoneurons controlling the diaphragm and upper airways.
The specific aim of this proposal is to determine the role the intrinsic properties of these motoneurons play in shaping their respiratory discharge behavior during development. More specifically, do intrinsic properties of the motoneuron control its neuronal behavior? The evolution of cellular and ionic mechanisms controlling this behavior will be studied during postnatal development. From these studies, we hope to ascertain if there is any difference in the process of maturation between these two motor pools and if so, what is the relative sequence of attaining their adult discharge characteristics? The active and passive membrane properties of these respiratory motoneurons will be investigated using intracellular recording and labeling techniques. The ionic mechanisms underlying these properties will be delineated using single electrode current and voltage clamp in both in vivo and in vitro mammalian preparations. An in vitro spinal cord and brainstem since will be developed in order to study the alteration in specific ionic currents during development.

National Institute of Health (NIH)
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
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Respiratory and Applied Physiology Study Section (RAP)
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Magee-Women's Hospital of Upmc
United States
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Carrascal, Livia; Nieto-Gonzalez, Jose Luis; Cameron, William E et al. (2005) Changes during the postnatal development in physiological and anatomical characteristics of rat motoneurons studied in vitro. Brain Res Brain Res Rev 49:377-87
Cameron, W E; Nunez-Abades, P A; Kerman, I A et al. (2000) Role of potassium conductances in determining input resistance of developing brain stem motoneurons. J Neurophysiol 84:2330-9
Nunez-Abades, P A; Pattillo, J M; Hodgson, T M et al. (2000) Role of synaptic inputs in determining input resistance of developing brain stem motoneurons. J Neurophysiol 84:2317-29
Robinson, D W; Cameron, W E (2000) Time-dependent changes in input resistance of rat hypoglossal motoneurons associated with whole-cell recording. J Neurophysiol 83:3160-4
Nunez-Abades, P A; Cameron, W E (1997) Relationship between membrane properties and cell size of developing rat genioglossal motoneurons studied in vitro. Neurosci Lett 223:41-4
Nunez-Abades, P A; Cameron, W E (1995) Morphology of developing rat genioglossal motoneurons studied in vitro: relative changes in diameter and surface area of somata and dendrites. J Comp Neurol 353:129-42
Nunez-Abades, P A; He, F; Barrionuevo, G et al. (1994) Morphology of developing rat genioglossal motoneurons studied in vitro: changes in length, branching pattern, and spatial distribution of dendrites. J Comp Neurol 339:401-20
Nunez-Abades, P A; Spielmann, J M; Barrionuevo, G et al. (1993) In vitro electrophysiology of developing genioglossal motoneurons in the rat. J Neurophysiol 70:1401-11
Mazza, E; Nunez-Abades, P A; Spielmann, J M et al. (1992) Anatomical and electrotonic coupling in developing genioglossal motoneurons of the rat. Brain Res 598:127-37
Cameron, W E; Jodkowski, J S; Fang, H et al. (1991) Electrophysiological properties of developing phrenic motoneurons in the cat. J Neurophysiol 65:671-9

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