Can common differences in our genes explain why some people are more sensitive to pain than others?

Evaluating the association of TRPA1 gene polymorphisms with pain sensitivity: A protocol for an adaptive recall by genotype study.

Status

Active, not recruiting

Phases

Unknown

Study type

Observational

Source

ISRCTN

Registry ID

ISRCTN16294731

Enrollment

100

Registered

2021-11-25

Start date

2020-01-27

Completion date

Unknown

Last updated

2022-01-24

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

The association of TRPA1 gene polymorphisms with pain sensitivity Not Applicable

Interventions

Five TRPA1 SNPs known to introduce missense mutations and with minor allele frequencies of >1% hypothesized to impact TRPA1 function will be investigated. The effect of these five SNPs will be assesse

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: Participants within the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort who are a regionally representative cross-sectional population aged around 30 years (with a correspondingly relatively low incidence of chronic pain).

Exclusion criteria

Exclusion criteria: 1. Neurological disorders including peripheral neuropathy 2. Regular use of analgesics 3. Any pain medication taken within 24 hours of QST 4. Pregnancy 5. Acute or Chronic pain conditions 6. Severe anxiety/depression 7. Allergy to cinnamon, mustard, alcohol / chlorhexidine wipes, latex. 8. Use of non-prescribed or recreational drugs (assessed by questionnaire).

Design outcomes

Primary

Measure	Time frame
Measured before and after 20 minute topical application of 10% cinnamaldehyde in ethanol: Heat pain threshold measured using a thermode (Medoc TSA-II, Medoc, Israel, or similar) on the right volar forearm. The temperature of the thermode will change at 1°C per second until the participant reports either detection of temperature change, or detection of pain via a mouse click. The thermode then returns to a neutral temperature of 32°C. The first trial will be discarded as an acclimatisation and then followed by 3 experimental repeats.	—

Measure

Time frame

Measured before and after 20 minute topical application of 10% cinnamaldehyde in ethanol: Heat pain threshold measured using a thermode (Medoc TSA-II, Medoc, Israel, or similar) on the right volar forearm. The temperature of the thermode will change at 1°C per second until the participant reports either detection of temperature change, or detection of pain via a mouse click. The thermode then returns to a neutral temperature of 32°C. The first trial will be discarded as an acclimatisation and then followed by 3 experimental repeats.

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Secondary

Measure	Time frame
Measured before and after 20 minute topical application of 10% cinnamaldehyde in ethanol: 1. CDT, cold detection threshold measured using the same method as the heat threshold with a cooled thermode 2. WDT, warm detection threshold measured using the same method as the heat threshold 3. CPT, cold pain threshold measured using using the same method as the heat threshold with a cooled thermode 4. MDT, mechanical detection threshold 5. MPT, mechanical pain threshold 6. MPS; mechanical pain sensitivity Thresholds for innocuous mechanical stimuli will be assessed using calibrated von Frey filaments (TouchTest; Stoelting, USA) via the method of levels. Mechanical pain thresholds, again via the method of limits, and stimulus response curves will be assessed using calibrated punctate needle stimulators (PinPricks; MRC Systems, Germany). For the stimulus response curve participant numerical pain ratings from 0 (no pain) to 100 (worst imaginable pain), will be assessed 5 times with 7 filaments exerting forces from 8 to 512mN presented in a randomised manner 7. Brush, presence or absence of brush allodynia measured with 5 standardised brush strokes (SenseLab; via MRC Systems, Germany) 8. Pressure, deep pressure pain threshold measured using an algometer (Somedic, Sweden) applied over the muscles of the right volar forearm 9. Axonal flare in response to cinnamaldehyde will be measured using full-field laser perfusion imaging (FLPI) of the target area of skin (moorFLPI-2; Moor Instruments)	—

Measure

Time frame

Measured before and after 20 minute topical application of 10% cinnamaldehyde in ethanol: 1. CDT, cold detection threshold measured using the same method as the heat threshold with a cooled thermode 2. WDT, warm detection threshold measured using the same method as the heat threshold 3. CPT, cold pain threshold measured using using the same method as the heat threshold with a cooled thermode 4. MDT, mechanical detection threshold 5. MPT, mechanical pain threshold 6. MPS; mechanical pain sensitivity Thresholds for innocuous mechanical stimuli will be assessed using calibrated von Frey filaments (TouchTest; Stoelting, USA) via the method of levels. Mechanical pain thresholds, again via the method of limits, and stimulus response curves will be assessed using calibrated punctate needle stimulators (PinPricks; MRC Systems, Germany). For the stimulus response curve participant numerical pain ratings from 0 (no pain) to 100 (worst imaginable pain), will be assessed 5 times with 7 filaments exerting forces from 8 to 512mN presented in a randomised manner 7. Brush, presence or absence of brush allodynia measured with 5 standardised brush strokes (SenseLab; via MRC Systems, Germany) 8. Pressure, deep pressure pain threshold measured using an algometer (Somedic, Sweden) applied over the muscles of the right volar forearm 9. Axonal flare in response to cinnamaldehyde will be measured using full-field laser perfusion imaging (FLPI) of the target area of skin (moorFLPI-2; Moor Instruments)

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Countries

England, United Kingdom

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Feb 13, 2026