Change in synaptic channel gating during neuromuscular development.

Abstract

FORMATION of neuromuscular synapses involves accumulation of acetylcholine receptors (AChRs) in the postsynaptic membrane1–5. The ionic channels associated with synaptic AChRs differ from the AChR channels present in the surface membrane of non-innervated muscle fibres. In particular, the mean open time of synaptic channels is much shorter than that of non-synaptic channels6–10. The question therefore arises at which stage of neuromuscular development the gating properties of synaptic channels become similar to those observed in adult junctions. The experiments described here show a difference in the mean open time of channels in early neonatal and adult rat endplates and suggest that a change in gating behaviour takes place during postnatal development.