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Multiple capsaicin-evoked currents in isolated rat sensory neurons
M Petersen1, R H Lamotte, A Klusch
1Department of Physiology, Julius Maximilian University Würzburg, Germany.
Neuroscience
|November 1, 1996
Summary
Capsaicin activates distinct ion current components in rat sensory neurons, suggesting multiple binding sites. This research clarifies capsaicin
Area of Science:
- Neuroscience
- Molecular Pharmacology
- Ion Channel Physiology
Background:
- Functional assays suggest capsaicin interacts with multiple molecular targets.
- Understanding these interactions is crucial for explaining diverse physiological responses to capsaicin.
Purpose of the Study:
- To investigate the hypothesis of multiple capsaicin binding sites using electrophysiological methods.
- To characterize distinct current components evoked by capsaicin in dorsal root ganglion cells.
Main Methods:
- Patch-clamp recordings from isolated rat dorsal root ganglion cells.
- Application of varying capsaicin concentrations in solutions with different ionic compositions.
- Investigation of current components' time-course, ion dependency, and response to pH changes.
Main Results:
- Capsaicin evoked up to three distinct, independently activated current components.
- Current components differed in activation kinetics, ion dependency (Na+, Ca2+), and concentration-dependence.
- Acidification and tachyphylaxis revealed distinct properties of the first two components, suggesting two binding sites.
Conclusions:
- Capsaicin elicits at least two distinct current components in sensory neurons, mediated by separate binding sites.
- These distinct components, differing in activation and properties, explain the varied physiological effects of capsaicin.