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Updated: Aug 3, 2026
09:09
Electrophysiological Investigations of Retinogeniculate and Corticogeniculate Synapse Function
Published on: August 7, 2019
Transport-mediated synapses in the retina
1Department of Neurobiology, Pharmacology, and Physiology, University of Chicago, Chicago, Illinois 60637, USA. eas@drugs.bsd.uchicago.edu
Physiological Reviews
|September 25, 2002
Summary
Some retinal synapses utilize transmitter transporters, not just exocytosis, to control neurotransmitter levels. This transport-mediated mechanism, observed in horizontal cells and cones, may function in other brain areas.
Area of Science:
- Neuroscience
- Cell Biology
- Synaptic Transmission
Background:
- Most synapses utilize regulated exocytosis to control neurotransmitter concentration in the synaptic cleft.
- This exocytotic mechanism may not be universally applied across all synapse types.
- Certain retinal synapses employ a distinct machinery where transmitter transporters are crucial.
Purpose of the Study:
- To investigate the role of transmitter transporters in synaptic function within the retina.
- To characterize transport-mediated synapses and their mechanisms.
- To explore the potential of these synapses as models for other brain regions.
Main Methods:
- Observation and analysis of synaptic machinery in horizontal cells and cones of nonmammalian retinas.
- Characterization of transporter function in mediating neurotransmitter release and reuptake.
- Investigation of the interplay between exocytosis, transporter activity, ion concentrations, and voltage.
Main Results:
- Two types of transport-mediated synapses have been identified, particularly in nonmammalian retinal horizontal cells and cones.
- Horizontal cells exhibit a bidirectional transporter shuttle influenced by ion concentrations and voltage.
- Nonmammalian cones integrate voltage-independent exocytosis with a voltage-dependent transporter to regulate synaptic cleft transmitter concentration.
Conclusions:
- Retinal synapses, specifically in horizontal cells and cones, demonstrate alternative mechanisms for neurotransmitter regulation involving transporters.
- Transport-mediated synaptic transmission, as exemplified in these retinal models, offers a different approach to controlling synaptic signaling.
- These findings suggest that transport-mediated synapses may represent a broader signaling principle applicable to neuronal communication in other parts of the central nervous system.
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