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Perception of specific trigeminal chemosensory agonists
J Frasnelli1, J Albrecht, B Bryant
1Monell Chemical Senses Center, Philadelphia, PA, USA. frasnelli@yahoo.com
Neuroscience
|May 18, 2011
Summary
The intranasal trigeminal system, a third chemical sense, shows related but distinct sensitivities. Measuring response to one chemical stimulus may suffice to assess overall trigeminal chemosensitivity.
Area of Science:
- Neuroscience
- Chemosensation
- Sensory Physiology
Background:
- The intranasal trigeminal system acts as a third chemical sense alongside olfaction and gustation.
- Understanding the link between receptor binding and perception in the trigeminal system remains limited.
- This study investigates trigeminal system sensitivity to specific receptor agonists.
Purpose of the Study:
- To investigate the sensitivity of the intranasal trigeminal system to agonists of TRPM8 and TRPA1 receptors.
- To assess the relationship between stimulus intensity and lateralization scores.
- To explore potential additive or suppressive effects in mixtures of trigeminal stimuli.
Main Methods:
- Subjects identified stimulated nostrils in a monorhinal stimulation design to calculate lateralization scores.
- Stimuli included menthol (TRPM8), eucalyptol (TRPM8), mustard oil (TRPA1), and their mixtures.
- Intensity evaluations and lateralization scores were analyzed for single compounds and mixtures.
Main Results:
- All tested stimuli were lateralized significantly above chance, indicating detectable trigeminal stimulation.
- Lateralization scores for compounds activating the same receptor correlated more strongly than for those activating different receptors.
- A mixture of menthol and eucalyptol (TRPM8 agonists) showed suppression effects, perceived as weaker and less accurately lateralized than a mixture activating both TRPM8 and TRPA1.
Conclusions:
- Sensitivity across different trigeminal sensory neuron subpopulations is related but not identical.
- High coherence in sensitivity suggests a single trigeminal chemical stimulus may predict overall chemosensitivity.
- Mixture suppression occurs for stimuli activating the same receptor, mirroring findings in other chemosensory systems.
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