Effects of serotonin on retinotectal-, corticotectal-, and glutamate-induced activity in the superior colliculus of the hamster
| Autor: | Xiaoguang Huang, R. D. Mooney, Robert W. Rhoades |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Serotonin
Superior Colliculi medicine.medical_specialty Physiology Glutamic Acid Hamster Stimulation Synaptic Transmission Retina Glutamates Cricetinae Internal medicine medicine Animals Visual Pathways Visual Cortex Neurons Iontophoresis Chemistry General Neuroscience Superior colliculus Glutamate receptor Neural Inhibition Electric Stimulation Electrophysiology Endocrinology Receptive field Evoked Potentials Visual Neuroscience Photic Stimulation |
| Zdroj: | Journal of Neurophysiology. 70:723-732 |
| ISSN: | 1522-1598 0022-3077 |
| DOI: | 10.1152/jn.1993.70.2.723 |
| Popis: | 1. Single-unit recording and iontophoretic techniques were used to test the effects of serotonin (5-HT) on the responses of neurons in the superficial layers (the stratum griseum superficiale and stratum opticum) of the hamster's superior colliculus (SC). 2. Iontophoresis of 5-HT produced a visual response suppression of 40% or greater in 78.1% (n = 50) of 64 neurons tested. 5-HT did not augment the visual responses of any of the cells tested. The average response suppression was 75.3 +/- 21.2% (mean +/- S.D.). 3. Iontophoresis of 5-HT had significantly different effects on activation of SC cells by optic chiasm (OX) and visual cortical (CTX) stimulation. Application of 5-HT suppressed the OX-evoked responses of 96.9% (n = 31) of the 32 SC cells tested by at least 40%, and the average response suppression for all 32 neurons tested was 87.1 +/- 22.5%. Application of 5-HT suppressed the responses of only 35.7% (n = 10) of the 28 cells tested with CTX stimulation by at least 40%. The average response suppression for all 28 cells was 35.3 +/- 38.8%. 4. The effects of 5-HT on the glutamate-evoked responses of SC cells that were synaptically "isolated" by concurrent application of Mg2+ were also evaluated. Application of 5-HT produced a response suppression > or = 40% in 29.7% (n = 19) of the 64 neurons tested under these conditions. The average response suppression for all of the cells tested was 28.4 +/- 35.7%. This effect of 5-HT was significantly weaker than that on visually evoked responses of these neurons. 5. The present results demonstrate that 5-HT markedly depresses the visual responses of most superficial layer SC neurons. They suggest further that much of this effect is mediated by presynaptic inhibition of retinotectal transmission. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|