An electrophysiological analysis of development at an identified molluscan synapse /

• Main Author: Pawson, Peter A.
• Format: Others
• Language: en
• Published: McGill University 1982
• Subjects: Synapses.; Developmental neurobiology.; Mollusks > Nervous system.
• Online Access: http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68674

Transmission at an identified chemical synapse between two giant molluscan neurones, in the snail Achatina fulica, was sampled continuously from late embryogenesis to adulthood. The laboratory culture and reproductive life-cycle of the snail are described. The propagation of spontaneous excitatory postsynaptic potentials (Epsps) into the postsynaptic soma was documented throughout development. Short-term facilitation (Epsp(,2)/Epsp(,1)) was present at the identified synapse at all ages studied. Over a series of 100 trials, embryonic synapse showed a net synaptic depression; while, postembryonically, there was a progressive increase in frequency-facilitation with increasing age. A quantal analysis of transmission indicates that the amplitude of the quantal unit declines in parallel with the decrease in the postsynaptic input resistance. There is a progressive (20-fold) increase in quantal content from embryos to adults. The developmental increase in transmission at the synapse is primarily presynaptic in origin. Structural correlates for the electrophysiological findings were discussed.