Aging and subcellular localization of m2 muscarinic autoreceptor in basalocortical neurons in vivo.
Neurobiology of Aging. 2005-07-01; 26(7): 1061-1072
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1. Neurobiol Aging. 2005 Jul;26(7):1061-72. Epub 2004 Nov 23.
Aging and subcellular localization of m2 muscarinic autoreceptor in
basalocortical neurons in vivo.
Décossas M(1), Doudnikoff E, Bloch B, Bernard V.
(1)Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5541,
Laboratoire d’Histologie-Embryologie, Université Victor Ségalen-Bordeaux 2, 146
rue Léo-Saignat, 33076 Bordeaux Cedex, France.
By using immunohistochemical approaches at the light and electron microscopic
levels, we have shown that aging modifies the subcellular distribution of the m2
muscarinic autoreceptor (m2R) differentially at somato-dendritic postsynaptic
sites and at axonal presynaptic sites in cholinergic basalocortical neurons, in
vivo. In cholinergic perikarya and dendrites of the nucleus basalis
magnocellularis (NBM), aging is associated with a decrease of the density of m2R
at the plasma membrane and in the cytoplasm, suggesting a decrease of the total
number of m2R in the somato-dendritic field. In contrast, the number of substance
P receptors per somato-dendritic surface was not affected. In the frontal cortex
(FC), we have shown a decrease of cytoplasmic m2R density also leading to a
decrease of the number of m2R per surface of varicosities but with no change of
the density of m2R at the membrane. Our results suggest that the decrease of m2R
in the somato-dendritic field of the NBM, but not a modification of the number of
presynaptic m2 autoreceptors at the plasma membrane in the FC, could contribute
to the decrease of the efficacy of cholinergic transmission observed with aging
in the rat.
PMID: 15748786 [Indexed for MEDLINE]