Involvement of neurotrophin-3 (NT-3) in the functional elimination of synaptic contacts during neuromuscular development.
Confocal immunohistochemistry shows that neurotrophin-3 (NT-3) and its receptor tropomyosin-related tyrosin kinase C (trkC) are present in both neonatal (P6) and adult (P45) mouse motor nerve terminals in neuromuscular junctions (NMJ) colocalized with several synaptic proteins. NT-3 incubation (1-3h, in the range 10-200ng/ml) does not change the size of the evoked and spontaneous endplate potentials at P45. However, NT-3 (1h, 100ng/ml) strongly potentiates evoked ACh release from the weak (70%) and the strong (50%) axonal inputs on dually innervated postnatal endplates (P6) but not in the most developed postnatal singly innervated synapses at P6. The present results indicate that NT-3 has a role in the developmental mechanism that eliminates redundant synapses though it cannot modulate synaptic transmission locally as the NMJ matures.
Garcia
Neus
N
Unitat d'Histologia i Neurobiologia (UHN), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i Virgili, Carrer Sant Llorenç, 21, 43201 Reus, Spain. ngs@fmcs.urv.es <ngs@fmcs.urv.es>
Santafé
Manel M
MM
Tomàs
Marta
M
Lanuza
Maria A
MA
Besalduch
Nuria
N
Tomàs
Josep
J
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D005071:Evoked Potentials; D019706:Excitatory Postsynaptic Potentials; D066298:In Vitro Techniques; D051379:Mice; D009045:Motor Endplate / Q000254:growth & development / Q000502:physiology; D009414:Nerve Growth Factors / Q000378:metabolism* / Q000494:pharmacology; D009469:Neuromuscular Junction / Q000254:growth & development / Q000502:physiology*; D017729:Presynaptic Terminals / Q000502:physiology; D020812:Receptor, trkC / Q000378:metabolism; D013569:Synapses / Q000502:physiology*
D009414:Nerve Growth Factors; C518911:neurotropin 3, mouse; D020812:Receptor, trkC; D000109:Acetylcholine