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Glycine-like immunoreactive input to sympathetic preganglionic neurons
J B Cabot1, V Alessi, A Bushnell
1Department of Neurobiology and Behavior, State University of New York, Stony Brook 11794-5230.
Brain Research
|January 31, 1992
Summary
This study investigated glycine-like immunoreactive processes in rat and pigeon sympathetic preganglionic neuropils. Glycine likely functions as a neurotransmitter in terminals synapsing with sympathetic preganglionic neurons.
Area of Science:
- Neuroscience
- Cell Biology
- Immunohistochemistry
Background:
- Sympathetic preganglionic neurons (SPNs) are crucial for autonomic functions.
- The neurotransmitters involved in SPN regulation are not fully understood.
Purpose of the Study:
- To investigate the organization and distribution of glycine-like immunoreactive (GLY-LIR) processes within the sympathetic preganglionic neuropils of rats and pigeons.
- To determine the ultrastructural characteristics of GLY-LIR terminals and their synaptic relationships with SPNs.
Main Methods:
- Retrograde labeling of SPNs using horseradish peroxidase.
- Immunoperoxidase and immunogold labeling techniques to visualize GLY-LIR processes.
- Light and electron microscopy for ultrastructural analysis.
Main Results:
- GLY-LIR puncta and terminal-like swellings were abundant in the neuropils of both species, closely apposing SPNs and their dendrites.
- Differences in GLY-LIR terminal density were observed across different subnuclei in rats.
- Ultrastructural analysis revealed symmetric synaptic specializations in 98% of GLY-LIR terminals, suggesting inhibitory neurotransmission.
Conclusions:
- Glycine is a likely neurotransmitter localized in terminals presynaptic to sympathetic preganglionic perikarya and dendrites.
- These findings contribute to understanding the neurochemical control of sympathetic preganglionic neurons.