Optical analysis of circuitry for respiratory rhythm in isolated brainstem of foetal mice.

Full Abstract

Respiratory rhythms arise from neurons situated in the ventral medulla. We are investigating their spatial and functional relationships optically by measuring changes in intracellular calcium using the fluorescent, calcium-sensitive dye Oregon Green 488 BAPTA-1 AM while simultaneously recording the regular firing of motoneurons in the phrenic nerve in isolated brainstem/spinal cord preparations of E17 to E19 mice. Responses of identified cells are associated breath by breath with inspiratory and expiratory phases of respiration and depend on CO(2) and pH levels. Optical methods including two-photon microscopy are being developed together with computational analyses. Analysis of the spatial pattern of neuronal activity associated with respiratory rhythm, including cross-correlation analysis, reveals a network distributed in the ventral medulla with intermingling of neurons that are active during separate phases of the rhythm. Our experiments, aimed at testing whether initiation of the respiratory rhythm depends on pacemaker neurons, on networks or a combination of both, suggest an important role for networks.

Author information

Author/s: Muller, Kenneth J (KJ); Tsechpenakis, Gavriil (G); Homma, Ryota (R); Nicholls, John G (JG); Cohen, Lawrence B (LB); Eugenin, Jaime (J);

Affiliation: Department of Physiology and Biophysics and Neuroscience Program, University of Miami School of Medicine, Miami, FL 33134, USA. kmuller(-atsign-)miami.edu

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't; Review

Journal: Philosophical transactions of the Royal Society of London. Series B, Biological sciences (Philos Trans R Soc Lond B Biol Sci), published in England. (Language: eng)

Reference: 2009-Sep; vol 364 (issue 1529) : pp 2485-91

Dates: Created 2009/08/04; Completed 2009/10/30;

PMID: 19651650, status: MEDLINE (last retrieval date: 10/30/2009, IMS Date: )

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Animals
Brain Stem - anatomy & histology; physiology
Calcium - metabolism
Carbon Dioxide - metabolism
Fetus - physiology
Fluorescent Dyes

Fluorescent Dyes
Mice
Microscopy, Fluorescence - methods
Nerve Net - anatomy & histology; physiology
Organic Chemicals
Respiratory Mechanics - physiology

Associated Chemicals: Fluorescent Dyes (0) ; Oregon Green BAPTA-dextran (0) ; Organic Chemicals (0) ; Carbon Dioxide (124-38-9) ; Calcium (7440-70-2)

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