Inhibitory conductance changes at synapses in the lamprey brainstem.

Area of Science:

• Neuroscience
• Synaptic Physiology
• Molecular Biology

Background:

• Inhibitory synaptic channel function is well-studied in peripheral cells.
• Detailed studies in the vertebrate central nervous system are lacking.
• Understanding natural synaptic events is crucial.

Purpose of the Study:

• Investigate inhibitory synaptic channels in the vertebrate central nervous system.
• Characterize channel kinetics and conductance at Müller cell synapses.
• Determine the role of glycine as a natural inhibitory transmitter.

Main Methods:

• Utilized current noise measurements for detailed analysis.
• Applied glycine to activate synaptic channels.
• Recorded spontaneous inhibitory synaptic currents.

Main Results:

• Glycine activated channels with large conductances (70 pS) and long time constants (33 ms).
• Spontaneous currents exhibited similar kinetics and reversal potentials.
• Strychnine abolished both glycine responses and spontaneous currents.

Conclusions:

• Glycine is identified as the natural inhibitory transmitter at these synapses.
• A single quantum of glycine likely activates approximately 1500 conductance channels.
• Provides insights into inhibitory neurotransmission in the central nervous system.