title: Phosphorylation reactions in activity-dependent synapse modification at the neuromuscular junction during development.
abstract: We have studied developmental activity-dependent synapse diminution in both an in vitro tissue culture chamber system and at the intact rodent neuromuscular junction (nmj). In both types of preparations, pre- and postsynaptic alterations in synapse structure and function are produced by manipulations of thrombin (Thr) and protein kinase C (PKC) activity. An opposing postsynaptic effect of PKC and protein kinase A (PKA) action on the acetycholine receptor (AChR) can be shown in vitro with PKA stabilizing and PKC destabilizing the nmj synapses. In vivo studies of normal junctional maturation show that changes in axonal inputs and postsynaptic receptor cluster morphology occur, to a substantial degree, independently of one another. Presynaptic actions of PKA are involved in the activity dependent synapse modulation that can be demonstrated in vitro. Late in the elimination process, (>12 days in vivo ) the process becomes independent of PKC, implying that diverse, redundant mechanisms are involved in this important developmental process.
authors.affiliation: Section on Neurobiology, Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development/NIH, Bethesda, MD 20892-4480, USA. pgnelson@codon.nih.gov
authors.forename: Phillip G
authors.initials: PG
authors.lastname: Nelson
authors.forename: Maria A
authors.initials: MA
authors.lastname: Lanuza
authors.forename: Min
authors.initials: M
authors.lastname: Jia
authors.forename: Min-Xu
authors.initials: MX
authors.lastname: Li
authors.forename: Josep
authors.initials: J
authors.lastname: Tomas
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D006801:Humans; D009469:Neuromuscular Junction / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000494:pharmacology; D013569:Synapses / Q000187:drug effects / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology
chemical_list: D011493:Protein Kinase C; D013917:Thrombin