The thrombin receptor mediates functional activity-dependent neuromuscular synapse reduction via protein kinase C activation in vitro

J Neurobiol. 1999 Feb 15;38(3):369-81.


Activity-dependent selective reduction of synaptic efficacy is expressed in an in vitro system involving mouse spinal cord and muscle cells. Thrombin or electrical stimulation of the innervating axons induces a decrease in neuromuscular synapse strength, and a specific thrombin inhibitor, hirudin, blocks the electrically evoked down-regulation of synapse effectiveness. We further demonstrate that a thrombin receptor-activating peptide (TRAP), SFLLRNPNDKYEPF, produces a decrement of synapse strength. Both TRAP and electrically evoked synapse decrement are prevented by the specific protein kinase C blocker calphostin C, and the TRAP-evoked synapse decrement is unaffected by a specific protein kinase A blocker, H-89. Thus, we propose that muscle activity, thrombin release, and thrombin receptor and PKC activation are initial steps in the process of the activity-dependent synapse reduction expressed in our system.

MeSH terms

  • Action Potentials / physiology
  • Amino Acid Sequence
  • Animals
  • Electric Stimulation
  • Enzyme Activation / physiology
  • Enzyme Inhibitors / pharmacology
  • Mice
  • Molecular Sequence Data
  • Motor Neurons / physiology
  • Neuromuscular Junction / physiology*
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / physiology*
  • Receptors, Thrombin / physiology*
  • Synapses / physiology*


  • Enzyme Inhibitors
  • Receptors, Thrombin
  • Protein Kinase C