Developmental Changes in the Nicotinic Acetylcholine Receptor in Mouse Tongue Striated Muscle

Abstract

There are no published studies on synaptogenesis focusing on the elimination of the superfluous nicotinic acetylcholine receptor (nAChR) outside the neuromuscular junction and the nAChR subunit switch from the embryonic-type (α₂βγδ subunits) to the adult-type (α₂β∈δ subunits) in mouse tongues. To identify the time course of nAChR subunit elimination and switch, we analyzed the expression levels of a, e, and γ subunit mRNAs, and the immunolocalization of the 8 subunit protein in the mouse tongue and corresponding hind limb. The analysis included the period from embryonic day (E) 11 to the newborn stage. The nAChR elimination and subunit switch began at E15 in the tongue and at E17 in the hind limb. They were nearly complete at birth in the tongue, but not in the hind limb. The early completion of synaptogenesis in the tongue at birth may be related to the early functional demands placed on the tongue, such as suckling and swallowing, immediately after birth.

Keywords

synaptogenesis AChR a e and γ subunits tongue muscle competitive RT-PCR confocal laser scanning microscope.

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