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Studies on convulsants in the isolated frog spinal cord. II. Effects on root potentials
The Journal of Physiology
|March 1, 1975
Summary
Neurotransmitters in frog spinal cord were studied using picrotoxin and strychnine. Picrotoxin blocked dorsal root potentials, while strychnine affected ventral root potentials, suggesting different neurotransmitters mediate these responses.
Area of Science:
- Neuroscience
- Neurophysiology
- Pharmacology
Background:
- Synaptically induced root potentials in the isolated frog spinal cord are crucial for understanding neural pathways.
- Investigating the effects of specific antagonists helps elucidate the neurotransmitters involved in these potentials.
Purpose of the Study:
- To evaluate the effects of picrotoxin, bicuculline, and strychnine on synaptically induced root potentials in the frog spinal cord.
- To identify the neurotransmitters mediating different spinal cord pathways.
Main Methods:
- Isolated frog spinal cord preparation.
- Sucrose gap technique for recording root potentials.
- Application of picrotoxin, bicuculline, and strychnine at various concentrations.
Main Results:
- Picrotoxin completely blocked ventral root-dorsal root potentials (VR-DRP) but revealed a picrotoxin-resistant component in dorsal root-dorsal root potentials (DR-DRP) and lateral column-dorsal root potentials (LC-DRP).
- Strychnine abolished VR-DRP and prolonged DR-DRP, LC-DRP, and dorsal root ventral root potentials (DR-VRP).
- High-concentration strychnine affected afferent fiber action potentials.
Conclusions:
- A gamma-aminobutyric acid (GABA)-like transmitter likely mediates the final step in DR-DRP and LC-DRP pathways.
- Taurine or beta-alanine may mediate the final step in the VR-DRP pathway.