Molecular and functional asymmetry at a vertebrate electrical synapse
John E Rash1, Sebastian Curti, Kimberly G Vanderpool
1Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
Neuron
|September 10, 2013
Summary
Electrical synapses in goldfish Mauthner cells exhibit molecular asymmetry, with distinct connexins forming presynaptic and postsynaptic hemichannels. This asymmetry rectifies electrical transmission, potentially enhancing auditory afferent cooperativity.
Area of Science:
- Neuroscience
- Cell Biology
- Molecular Biology
Background:
- Electrical synapses are crucial for rapid neuronal communication in the vertebrate brain.
- Their molecular composition and functional implications remain incompletely understood.
- Understanding electrical synapse structure is key to deciphering neural circuit function.
Purpose of the Study:
- To elucidate the molecular architecture of electrical synapses between goldfish auditory afferents and Mauthner cells.
- To investigate the functional consequences of molecular asymmetry in electrical synapses.
- To explore potential mechanisms of asymmetry in electrical synapses across species.
Main Methods:
- Immunohistochemistry to identify connexin distribution.
- Electrophysiological recordings to assess synaptic transmission.
- Molecular analysis of connexin homologs.
Main Results:
- Electrical synapses are formed by hemichannels of two connexin 36 (Cx36) homologs.
- Cx35 is localized to presynaptic hemiplaques, while Cx34.7 is restricted to postsynaptic hemiplaques, forming heterotypic junctions.
- This molecular asymmetry results in rectified electrical transmission.
Conclusions:
- Electrical synapses can exhibit molecular asymmetry, similar to chemical synapses.
- Asymmetry in goldfish involves distinct connexin homologs (Cx35 and Cx34.7).
- This asymmetry may facilitate cooperativity among auditory afferents and suggests diverse mechanisms for electrical synapse specialization.
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