Abstract
The extent to which retinal signals are modulated at central sites is unknown. We sought to determine the effects of serotonin, a neurotransmitter present in the retinorecipient layers of the frog tectum, on retinotectal transmission. Acute electrical stimulation delivered to the retinorecipient layer of optic tectum brain slices was used to model the activation of rectal neurons by visual inputs. This stimulation evoked either a monosynaptic or a polysynaptic current response in patch-clamped tectal neurons. External application of serotonin blocked both of these induced currents as did 5-carbotryptamine (5-CT), a nonselective agonist of 5-HT1 receptors. Alpha-methylserotonin, a nonselective agonist of 5-HT2 receptors, also blocked polysynaptic responses but was less effective than either serotonin or 5-CT in blocking monosynaptic ones. Lateral synaptic interactions between tectal cells, modeled by acute electrical stimulation in the main cellular layer of the tectum, were also blocked by serotonin, 5-CT or α-methylserotonin. The presented data suggest that endogenous serotonin may strongly affect visual signal processing by modulating synaptic transmission between both the retina and the tectum as well as between tectal neurons. This modulation is likely to be due, at least in part, to a demonstrated outward current induced by serotonin in a subpopulation of tectal cells.
Original language | English |
---|---|
Pages (from-to) | 167-181 |
Number of pages | 15 |
Journal | Brain Research |
Volume | 781 |
Issue number | 1-2 |
DOIs | |
State | Published - Jan 19 1998 |
Bibliographical note
Funding Information:We thank Drs. Martha Constantine-Paton, Peter Hickmott and Doug McMahon for their generosity in sharing equipment and their offering of technical expertise during this study. This work was supported by NSF grants IBN 92-09651 and IBN 95-14614.
Keywords
- 5-HT receptor
- 5-HT receptor
- Rana pipiens
- Topographic map formation
- Visual plasticity
- Visual system
ASJC Scopus subject areas
- General Neuroscience
- Molecular Biology
- Clinical Neurology
- Developmental Biology