Neurobiological and Psychophysical Mechanisms Underlying the Oral Sensation Produced by Carbonated Water

• Main Authors: C. T. Simons, J. -m. Dessirier, M. Iodi Carstens, E. Carstens
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Carbonic acid
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.323.1261; http://www.jneurosci.org/content/19/18/8134.full.pdf

Carbonated drinks elicit a sensation that is highly sought after, yet the underlying neural mechanisms are ill-defined. We hypothesize that CO 2 is converted via carbonic anhydrase into carbonic acid, which excites lingual nociceptors that project to the trigeminal nuclei. We investigated this hypothesis using three methodological approaches. Electrophysiological methods were used to record responses of single units located in superficial laminae of the dorsomedial aspect of trigeminal subnucleus caudalis (Vc) evoked by lingual application of carbonated water in anesthetized rats. After pretreatment of the tongue with the carbonic anhydrase inhibitor dorzolamide, neuronal responses to carbonated water were significantly attenuated, followed by recovery. Using c-Fos immunohistochemistry, we investigated the distribution of brainstem neurons activated by intraoral carbonated water. Fos-like immunoreactivity (FLI)