Cholinergic nerve terminals
July 16, 2011
eJ Comp Neurol. 2003 Jun 9;460(4):476-86.
Large cholinergic nerve terminals on subsets of motoneurons and their relation to muscarinic receptor type 2.
Hellström J, Oliveira AL, Meister B, Cullheim S.
SourceDepartment of Neuroscience, The Retzius Laboratory, Karolinska Institutet, SE-171 77 Stockholm, Sweden. firstname.lastname@example.org
The cholinergic C-bouton is a large nerve terminal found exclusively apposing motoneuron cell somata and proximal dendrites. The origin and function of the C-bouton is not known. An antiserum against the vesicular acetylcholine transporter was used to identify large cholinergic nerve terminals putatively of the C-type in close apposition to motoneuron cell somata. This type of nerve terminal was present in the rat spinal cord ventral horn, but only in some cranial motor nuclei. Fluoro-Gold tracing showed that subsets of spinal motoneuron cell somata were contacted by different numbers of putative C-boutons. Thus, motoneurons innervating an intrinsic foot muscle were contacted by about half the number of cholinergic terminals found on motoneurons of the predominantly fast-twitch gastrocnemius muscle. Slow-twitch soleus motoneurons showed an intermediate innervation. There was a strong correlation between the presence of putative C-boutons and muscarinic receptor 2 (m2)-like immunoreactivity (-LI) within a motor nucleus. By using confocal laser microscopy, the m2-LI appeared to be confined to the motoneuron cell membrane and strongly enriched beneath the C-type nerve terminal. Thus, our results suggested a differential distribution of large cholinergic C-boutons, depending on motoneuron type, and that the presence of this nerve terminal type is associated with m2-LI in the postsynaptic membrane.
Copyright 2003 Wiley-Liss, Inc.
PMID: 12717708 [PubMed - indexed for MEDLINE]
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