Expression of GABA(A) receptor alpha3-, theta-, and epsilon-subunit mRNAs during rat CNS development and immunolocalization of the epsilon subunit in developing postnatal spinal cord.
Neuroscience. 2009-04-01; 160(1): 85-96
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1. Neuroscience. 2009 Apr 21;160(1):85-96. doi: 10.1016/j.neuroscience.2009.02.043.
Epub 2009 Feb 26.
Expression of GABA(A) receptor alpha3-, theta-, and epsilon-subunit mRNAs during
rat CNS development and immunolocalization of the epsilon subunit in developing
postnatal spinal cord.
Pape JR(1), Bertrand SS, Lafon P, Odessa MF, Chaigniau M, Stiles JK, Garret M.
(1)Université de Bordeaux, CNRS, UMR 5228, France.
Ionotropic GABA(A) receptors are heteromeric structures composed of a combination
of five from at least 16 different subunits. Subunit genes are expressed in
distinct cell types at specific times during development. The most abundant
native GABA(A) receptors consist of alpha1-, beta2-, and gamma2-subunits that are
co-expressed in numerous brain areas. alpha3-, theta-, And epsilon-subunits are
clustered on the X chromosome and show striking overlapping expression patterns
throughout the adult rat brain. To establish whether these subunits are
temporally and spatially co-expressed, we used in situ hybridization to analyze
their expression throughout rat development from embryonic stage E14 to postnatal
stage P12. Each transcript exhibited a unique or a shared regional and temporal
developmental expression profile. The thalamic expression pattern evolved from a
restricted expression of epsilon and theta transcripts before birth, to a theta
and alpha3 expression at birth, and finally to a grouped epsilon, theta and
alpha3 expression postpartum. However, strong similarities occurred, such as a
grouped expression of the three subunits within the hypothalamus, tegmentum and
pontine nuclei throughout the developmental process. At early stages of
development (E17), epsilon and theta appeared to have a greater spatial
distribution before the dominance of the alpha3 subunit transcript around birth.
We also revealed expression of alpha3, theta, and epsilon in the developing
spinal cord and identified neurons that express epsilon in the postnatal dorsal
horn, intermediolateral column and motoneurons. Our findings suggest that various
combinations of alpha3-, theta- and epsilon-subunits may be assembled at a
regional and developmental level in the brain.
PMID: 19249336 [Indexed for MEDLINE]