Sodium chloride

Sensitisation data (human)

Administrative data

Endpoint:

sensitisation data (humans)

Type of information:

other: publication

Adequacy of study:

supporting study

Study period:

2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: It is a publication from Physiology and Behavior journal. There is no specific guideline followed mentioned in the report.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2000

Materials and methods

Type of sensitisation studied:

skin

Study type:

study with volunteers

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

no data

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Sodium chloride

EC Number:

231-598-3

EC Name:

Sodium chloride

Cas Number:

7647-14-5

Molecular formula:

ClNa

IUPAC Name:

sodium chloride

Details on test material:

- Name of test material (as cited in study report): Sodium Chloride

Method

Type of population:

general

Ethical approval:

not specified

Subjects:

- Number of subjects exposed: Twenty five healthy individuals
- Sex: 7 males and 18 females
- Age:18-27 years

Clinical history:

no data

Controls:

No data

Route of administration:

oral

Details on study design:

All subjects participated in an initial session to verify that the concentration of capsaicin yielded an intensity of irritation approximately equivalent to that of NaCl. One large filter paper disk soaked with 40 ml of the 3-ppm capsaicin solution was placed on to one side of the dorsal anterior surface of the tongue and another, soaked with 40 ml of the 5-M NaCl solution, was simultaneously placed onto the other side. The sides receiving capsaicin or NaCl were counterbalanced across subjects. After 15 s, subjects performed a 2-AFC test [30] by reporting which side of the tongue had a stronger sensation. Subjects then separately rated the intensity of irritation on each side using a category scale with the end points 0 (no sensation) and 10 (intense irritation). To assess changes in intensity over time, 2-AFC and rating tasks were repeated at 30-s intervals for a total period of 3 min during which the filter papers remained on the tongue.

Results and discussion

Results of examinations:

Fifteen seconds after capsaicin and NaCl were simultaneously applied to opposite sides of the tongue, 17 of 25 subjects chose the NaCl-stimulated side as yielding a stronger sensation. This was not a significant majority (binomial, P = .11). However, the mean ratings on the two sides of the tongue were significantly different (4.3 vs. 3.2; t test, P = .025). There was no significant difference 30 s or 1 min later. These results confirm the large degree of interindividual variability in perception of irritation from various compounds, and indicate that the NaCl J.-M. Dessirier et al. / Physiology & Behavior 72 (2001) 317±324 319 and capsaicin solutions were sufficiently well matched in intensity for present purposes.

Any other information on results incl. tables

None

Applicant's summary and conclusion

Conclusions:

Fifteen seconds after capsaicin and NaCl were simultaneously applied to opposite sides of the tongue, 17 of 25 subjects chose the NaCl-stimulated side as yielding a stronger sensation. This was not a significant majority (binomial, P = .11). However, the mean ratings on the two sides of the tongue were significantly different (4.3 vs. 3.2; t test, P = .025). There was no significant difference 30 s or 1 min later. These results confirm the large degree of interindividual variability in perception of irritation from various compounds, and indicate that the NaCl J.-M. Dessirier et al. / Physiology & Behavior 72 (2001) 317±324 319 and capsaicin solutions were sufficiently well matched in intensity for present purposes.

Executive summary:

Twenty-five healthy individuals (7 males, 18 females, age 18±27 years), who were students and staff at the University of California at Davis, volunteered to participate in the study. All refrained from eating or drinking at least 1 h prior to each experimental session, and were asked not to eat spicy food for 2 days prior to testing as verified by questionnaire.

All subjects participated in an initial session to verify that the concentration of capsaicin yielded an intensity of irritation approximately equivalent to that of NaCl. One large filter paper disk soaked with 40 ml of the 3-ppm capsaicin solution was placed on to one side of the dorsal anterior surface of the tongue and another, soaked with 40 ml of the 5-M NaCl solution, was simultaneously placed onto the other side. The sides receiving capsaicin or NaCl were counterbalanced across subjects. After 15 s, subjects performed a 2-AFC test [30] by reporting which side of the tongue had a stronger sensation. Subjects then separately rated the intensity of irritation on each side using a category scale with the end points 0 (no sensation) and 10 (intense irritation). To assess changes in intensity over time, 2-AFC and rating tasks were repeated at 30-s intervals for a total period of 3 min during which the filter papers remained on the tongue.

Fifteen seconds after capsaicin and NaCl were simultaneously applied to opposite sides of the tongue, 17 of 25 subjects chose the NaCl-stimulated side as yielding a stronger sensation. This was not a significant majority (binomial, P = .11). However, the mean ratings on the two sides of the tongue were significantly different (4.3 vs. 3.2; t test, P = .025). There was no significant difference 30 s or 1 min later. These results confirm the large degree of interindividual variability in perception of irritation from various compounds, and indicate that the NaCl J.-M. Dessirier et al. / Physiology & Behavior 72 (2001) 317±324 319 and capsaicin solutions were sufficiently well matched in intensity for present purposes.