Rationale: Injection of rat VAChT cDNA or synthetic mRNA into blastomeres of Xenopus embryos causes an overexpression of VAChT at the developing neuromuscular synapse, which is known to exhibit incomplete ACh filling of synaptic vesicles at this immature stage. Overexpression of VAChT in the presynaptic neurons causes an increase in the amplitude and frequency of spontaneous (action-potential independent) miniature excitatory postsynaptic currents measured by whole cell patch-clamp electrophysiology in postsynaptic muscle cells (Fig. 2). These findings indicate that VAChT regulates the neurotransmitter filling state of synaptic vesicles.. Experimental description: Rat VAChT cDNA or synthetic mRNA prepared from the cDNA was injected into one of the early blastomeres of Xenopus embryos at the 2-cell stage...