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Thermally evoked parotid salivation.
Andy Lee1, Steve Guest, Greg Essick
1Department of Biochemistry, North Carolina State University, Raleigh, NC, USA.
Physiology & Behavior
|March 15, 2006
Summary
Cold thermal stimuli applied to the tongue can significantly increase parotid salivation. This study shows that non-liquid temperature changes can evoke salivary responses, independent of oral movements.
Area of Science:
- Physiology
- Sensory Science
Background:
- Parotid salivation is known to be modulated by liquid temperature and oral movements.
- The influence of non-liquid thermal stimuli on salivation remains less understood.
Purpose of the Study:
- To investigate if non-liquid thermal stimuli can alter parotid salivation rates.
- To determine the effect of different temperatures applied statically to the tongue on salivation.
Main Methods:
- Unilateral parotid saliva was collected from 12 subjects using a Lashley Cup.
- Static thermal stimuli (10°C, 22°C, 44°C, and body temperature) were applied to the anterior tongue via a copper tube.
- Unstimulated and stimulated salivation rates were measured, alongside subjective ratings of temperature and wetness.
Main Results:
- A significant increase in parotid salivation was observed only with the 10°C stimulus applied to the tongue.
- Salivation rates differed significantly across temperatures and body sites (P<0.03).
- Subjective wetness ratings and salivation rates showed a weak positive correlation.
Conclusions:
- Temperature-evoked changes in parotid salivation can occur without the dynamic oral movements typically associated with liquid stimuli.
- Static cold application to the tongue is sufficient to stimulate parotid gland secretion.