Large cholinergic nerve terminals on subsets of motoneurons and their relation to muscarinic receptor type 2.
J Comp Neurol
; 460(4): 476-86, 2003 Jun 09.
Article
in En
| MEDLINE
| ID: mdl-12717708
ABSTRACT
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.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Membrane Transport Proteins
/
Spinal Cord
/
Stilbamidines
/
Carrier Proteins
/
Cholinergic Fibers
/
Receptors, Muscarinic
/
Presynaptic Terminals
/
Vesicular Transport Proteins
/
Motor Neurons
Limits:
Animals
Language:
En
Journal:
J Comp Neurol
Year:
2003
Type:
Article
Affiliation country:
Sweden