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Danica Berry Master's Thesis_Final.pdf (2.07 MB)

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Effect of oral cavity loci and cultural background on responses to capsaicin

Berry, Danica
http://rave.ohiolink.edu/etdc/view?acc_num=osu1586358754553389

Abstract Details

2020, Master of Science, Ohio State University, Food Science and Technology.
Capsaicin is a chemesthetic compound found in chili peppers that activates the receptor TRPV1 to elicit painful, burning sensations. Responses to capsaicin can be greatly decreased, or desensitized, following repeated exposure. Although the TRPV1 receptor is expressed ubiquitously throughout the human oral cavity, there is not a clear understanding of the behavior of many oral tissues in response to capsaicin. Additionally, the effect of cultural aspects outside of chili pepper affinity on capsaicin responses has not been clearly determined. Therefore, the goals of the present study were to (1) investigate capsaicin irritation and desensitization across oral cavity mucosae and (2) determine capsaicin sensitivity differences between cultures. Specifically, the first two aims were to determine differences in perception and characterize desensitization over time on the tongue, cheek, hard palate, and lip. The third study aim was to determine sensitivity differences across Caucasian American and Indian cultures by using a design controlling for chili pepper affinity. Caucasian Americans and Indians were recruited for Experiment 1 and completed a survey questionnaire. A chili pepper use and liking score (CPULS) was calculated for each potential subject recruit based on the survey responses. Participants were selected based on matching of chili pepper use frequencies and average CPULS between groups. To determine sensitivity on each oral cavity area, irritation intensity of a capsaicin stimulus (100 ppm) was measured over a 10-minute period. Area under the time-intensity curve (AUC), peak intensity, and time to peak intensity parameters were dependent variables derived from these ratings. Data were analyzed using ANOVA with sex, frequency of use, and oral cavity areas as factors. To characterize desensitization, capsaicin stimuli were applied to the capsaicin- and control-pretreated locations and subjects completed 2-AFC (Which side feels stronger?&) questions followed by intensity ratings over a 3.5-minute period. Binomial statistics and paired t-tests were used to analyze the data. Oral mucosal location was found to impact perceptual responses. Specifically, max intensity and overall intensity were greater on the tongue compared to hard palate, and the hard palate compared to cheek and lip, but did not differ between the cheek and lip. Time to reach max intensity was greater on the hard palate than on the tongue, cheek, and lip, but not among the latter three areas. Capsaicin desensitization investigated from the second task was clear on the tongue and hard palate but was not evident on the cheek and lip. Based on the lack of response differentiation and desensitization found on the cheek and lip in Experiment 1, a follow-up experiment was conducted. A greater capsaicin concentration (1000ppm) was utilized in Experiment 2 in order to evaluate the cheek and the lip. Results from Experiment 2, which utilized a higher capsaicin concentration, showed that the responses on the lip were greater than on the cheek, and desensitization was observable on both areas. However, desensitization was observed to a lesser extent on the cheek than the lip. The Caucasian American and Indian sample groups in Experiment 1 were well matched and did not differ in age, frequency of consumption, or chili pepper use and liking score (CPULS) (p’s>0.05). Results demonstrated that, after controlling for these external factors, there were no significant effects of cultural group, sex, or frequency of chili pepper use on AUC or peak intensity. This research demonstrates that oral cavity areas differ in their responsiveness over time to capsaicin and the extent of perceivable desensitization. The findings here likely serve as indicators of differing sensitivity across the tissues which may be the result of epithelial tissue type and receptor density differences. The controlled design of this study which tightly matched subject cohorts also allowed us to determine that there were no sensitivity differences to capsaicin between Indians and Caucasian Americans. These data support that differences in responsiveness to capsaicin may be the result of controlled factors such as chili pepper use and liking rather than other cultural attributes.
Christopher Simons, Dr. (Advisor)
Monica Giusti, Dr. (Committee Member)
Devin Peterson, Dr. (Committee Member)
95 p.
Food Science
perception; sensitivity; hard palate; tongue; analgesic; ethnicity;

Recommended Citations

Citations

  • Berry, D. (2020). Effect of oral cavity loci and cultural background on responses to capsaicin [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1586358754553389

    APA Style (7th edition)

  • Berry, Danica. Effect of oral cavity loci and cultural background on responses to capsaicin. 2020. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1586358754553389.

    MLA Style (8th edition)

  • Berry, Danica. "Effect of oral cavity loci and cultural background on responses to capsaicin." Master's thesis, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1586358754553389

    Chicago Manual of Style (17th edition)

osu1586358754553389
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