Measurement notes
Document whether the assay uses radiant heat or immersion, where the stimulus is applied, how the animal is restrained, and how repeated trials rotate tail positions. Preserve both raw and cutoff-clamped latencies when possible.
Endpoint methods library
Spinal thermal reflex endpoint
Tail flick latency
Time from radiant heat or tail-immersion stimulus onset to tail withdrawal, flick, or removal according to a predefined cutoff rule.
Unit
seconds
Readout
Latency from heat stimulus onset to tail flick, withdrawal, or removal
Assays
Radiant heat tail flick, tail immersion, analgesic dose-response, tolerance studies
Decision summary
Use tail flick latency when the experiment needs a compact thermal reflex endpoint, especially for spinal nociceptive transmission or opioid antinociception workflows. The assay should be paired with baseline latency, stimulus intensity, tail temperature, and motor/sedation controls before drawing pharmacological conclusions.
| Primary value | Latency from heat stimulus onset to tail flick, withdrawal, or removal |
|---|---|
| Common units | Seconds, commonly capped by a short tissue-protection cutoff |
| Compatible assays | Radiant heat tail flick, tail immersion, analgesic dose-response, tolerance studies |
| Required boundary | Stimulus intensity, tail location, restraint method, and cutoff rule |
| Do not infer alone | Pain affect, supraspinal processing, broad analgesia, or motor competence |
Interpretation limit
Longer latency can support reduced nociceptive reflex responding, but it may also arise from low stimulus intensity, cold tail temperature, poor beam placement, restraint stress, sedation, or motor impairment. Tail flick is not a full substitute for supraspinal or spontaneous pain measures.
Data capture
Store animal ID, group, trial number, stimulus type, stimulus intensity or water temperature, tail position, restraint type, cutoff, raw latency, clamped latency, baseline latency, time since dose, and exclusion notes.
Confound checks
- Tail temperature, circulation, pigmentation, or local tissue condition.
- Beam placement, immersion depth, stimulus intensity, or water temperature drift.
- Restraint stress, struggling, or inconsistent habituation.
- Repeated stimulation of the same tail region without rotation.
- Sedation, motor impairment, hypothermia, or drug effects on reflex output.
Reporting checklist
- Radiant heat or immersion method, stimulus intensity, tail position, and cutoff.
- Restraint method, acclimation, trial count, and inter-trial interval.
- Baseline latency, post-treatment window, and dose-to-test interval.
- Whether values were raw, cutoff-clamped, averaged, or converted to percent maximum possible effect.
- Rules for excluding movement artifacts, struggling, or equipment misfires.
- Companion endpoints used to separate spinal reflex effects from sedation or supraspinal nociception.
References
Evidence notes
Endpoint pages should cite the method literature behind the scored value and keep high-specificity protocol claims qualified unless the source supports them.
- D'Amour FE, Smith DL. A method for determining loss of pain sensation. J Pharmacol Exp Ther. 1941;72:74-79.
- Le Bars D, Gozariu M, Cadden SW. Animal models of nociception. Pharmacol Rev. 2001. doi:10.1124/pr.53.4.597.
- Deuis JR, Dvorakova LS, Vetter I. Methods used to evaluate pain behaviors in rodents. Front Mol Neurosci. 2017. doi:10.3389/fnmol.2017.00284.
Related workflow paths
Endpoint articles link to adjacent products, software workflows, and sibling endpoints where the connection is useful and already routable.
Tail flick latency calculator
Summarize repeated tail flick trials with cutoff clamping and group SEM.
Pain percent maximum effect calculator
Normalize baseline and post-treatment latency against the protocol cutoff.
Hot plate latency endpoint
Pair tail flick with a heated-surface assay when supraspinal response context matters.
