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Differential expression of connexin26 and connexin32 in the pre-Bötzinger complex of neonatal and adult rat

Authors

  • Irene C. Solomon,

    Corresponding author
    1. Department of Physiology and Biophysics, State University of New York at Stony Brook, Stony Brook, New York 11794-8661
    • Department of Physiology and Biophysics, Basic Science Tower T6 Room 140, State University of New York at Stony Brook, Stony Brook, NY 11794-8661
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  • Tami J. Halat,

    1. Department of Physiology and Biophysics, State University of New York at Stony Brook, Stony Brook, New York 11794-8661
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    • T.J. Halat and M.H. O'Neal contributed equally to this work.

  • Raafat El-Maghrabi,

    1. Department of Physiology and Biophysics, State University of New York at Stony Brook, Stony Brook, New York 11794-8661
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  • Marvin H. O'Neal III

    1. Department of Physiology and Biophysics, State University of New York at Stony Brook, Stony Brook, New York 11794-8661
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    • T.J. Halat and M.H. O'Neal contributed equally to this work.


Abstract

The pre-Bötzinger complex (pre-BötC) is hypothesized to be the site for respiratory rhythm generation in mammals. Studies examining the cellular mechanisms mediating rhythm generation have focused on the role of chemically mediated synaptic interactions; however, electrotonic synaptic interactions (i.e., electrotonic coupling), which occur by means of gap junctions, may also play a role. Here, we used immunoblot and immunohistochemical analyses to determine whether the pre-BötC contains the gap junction proteins necessary for electrotonic communication and whether the presence and distribution of these gap junction proteins show a developmental change in expression. We found that both connexin26 (Cx26) and connexin32 (Cx32) were expressed in pre-BötC neurons of neonatal and adult rats; however, the relative amounts and their distribution varied by age. Cx26 labeling was seen in a high proportion of pre-BötC neurons in neonatal rats ≤ 7 days postnatal (P7) but declined with increasing age. In contrast, Cx32 labeling was sparse in pre-BötC neurons of neonatal rats ≤ P7, but increased with increasing age; the highest proportion was seen in adult rats. These data suggest the potential for gap junctional communication in the pre-BötC of both neonatal and adult rats, and we propose that the gap junction proteins Cx26 and Cx32 form the neuroanatomic substrate for this gap junctional communication, which may be important in the synchronization of neural activity generating respiratory rhythm.J. Comp. Neurol. 440:12–19, 2001. © 2001 Wiley-Liss, Inc.

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