RGD Reference Report - Modulation of ACh release by presynaptic muscarinic autoreceptors in the neuromuscular junction of the newborn and adult rat. - Rat Genome Database

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Modulation of ACh release by presynaptic muscarinic autoreceptors in the neuromuscular junction of the newborn and adult rat.

Authors: Santafe, MM  Salon, I  Garcia, N  Lanuza, MA  Uchitel, OD  Tomas, J 
Citation: Santafe MM, etal., Eur J Neurosci 2003 Jan;17(1):119-27.
RGD ID: 724727
Pubmed: PMID:12534975   (View Abstract at PubMed)

We studied the presynaptic muscarinic autoreceptor subtypes controlling ACh release and their relationship with voltage-dependent calcium channels in the neuromuscular synapses of the Levator auris longus muscle from adult (30-40 days) and newborn (3-6 and 15 days postnatal) rats. Using intracellular recording, we studied how several muscarinic antagonists affected the evoked endplate potentials. In some experiments we previously incubated the muscle with calcium channel blockers (nitrendipine, omega-conotoxin-GVIA and omega-Agatoxin-IVA) before determining the muscarinic response. In the adult, the M1 receptor-selective antagonist pirenzepine (10 micro m) reduced evoked neurotransmission ( approximately 47%). The M2 receptor-selective antagonist methoctramine (1 micro m) increased the evoked release ( approximately 67%). Both M1- and M2-mediated mechanisms depend on calcium influx via P/Q-type synaptic channels. We found nothing to indicate the presence of M3 (4-DAMP-sensitive) or M4 (tropicamide-sensitive) receptors in the muscles of adult or newborn rats. In the 3-6-day newborn rats, pirenzepine reduced the evoked release ( approximately 30%) by a mechanism independent of L-, N- and P/Q-type calcium channels, and the M2 antagonist methoctramine (1 micro m) unexpectedly decreased the evoked release ( approximately 40%). This methoctramine effect was a P/Q-type calcium-channel-dependent mechanism. However, upon maturation in the first two postnatal weeks, the M2 pathway shifted to perform the calcium-dependent release-inhibitory activity found in the adult. We show that the way in which M1 and M2 muscarinic receptors modulate neurotransmission can differ between the developing and adult rat neuromuscular synapse.



Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process

  
Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
Chrm1RatG protein-coupled acetylcholine receptor signaling pathway  IDA  RGD 
Chrm2RatG protein-coupled acetylcholine receptor signaling pathway  IDA  RGD 
Chrm1Ratneuromuscular synaptic transmission  IDA  RGD 

Molecular Function

  
Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
Chrm1RatG protein-coupled acetylcholine receptor activity  IDA  RGD 
Chrm2RatG protein-coupled acetylcholine receptor activity  IDA  RGD 

Objects Annotated

Genes (Rattus norvegicus)
Chrm1  (cholinergic receptor, muscarinic 1)
Chrm2  (cholinergic receptor, muscarinic 2)


Additional Information