Thermal nociception endpoint

Hot plate latency

Time from placement on a heated plate to a predefined nocifensive response such as hindpaw licking, withdrawal, shaking, or jumping.

Unit

seconds

Readout

Latency from plate placement to the first predefined nocifensive response

Assays

Hot plate analgesia, thermal hyperalgesia, dose-response analgesic screening, tolerance studies

Decision summary

Use hot plate latency when the experiment needs a thermal nociception readout with a supraspinal response component. The endpoint is useful for analgesic screening and heat hyperalgesia work, but it should not be interpreted as pain intensity by itself. Interpretation is strongest when plate temperature, response criterion, cutoff, baseline latency, locomotor state, and sedation controls are fixed before testing.

Primary value	Latency from plate placement to the first predefined nocifensive response
Common units	Seconds, usually capped at a protocol-defined cutoff
Compatible assays	Hot plate analgesia, thermal hyperalgesia, dose-response analgesic screening, tolerance studies
Required boundary	Plate temperature, response definition, timer start, timer stop, and cutoff rule
Do not infer alone	Pain affect, drug efficacy, peripheral sensitivity, sedation, or motor competence

Measurement notes

Predefine the response list and apply the same rule to every animal. Common scoring endpoints include hindpaw lick, hindpaw withdrawal or shake, and jump. Record the plate temperature, cutoff, timer start rule, and whether ambiguous grooming or rearing behaviors are excluded.

Interpretation limit

Longer latency can support antinociception, but it can also reflect sedation, impaired motor output, altered attention, hypothermia, handling stress, or a response criterion that is too broad. Shorter latency may reflect hyperalgesia, anxiety-like escape, poor acclimation, or temperature drift.

Data capture

Store animal ID, group, trial number, plate temperature, cutoff, raw latency, cutoff-clamped latency, response type, baseline latency, time since dose, exclusion flag, observer, and apparatus verification notes.

Confound checks

Plate temperature drift or uneven heat distribution across the surface.
Different response definitions across observers or sessions.
Sedation, ataxia, weakness, hypothermia, or altered locomotor activity.
Repeated exposure without enough recovery time between trials.
Strain, sex, body weight, circadian timing, and acclimation differences.

Reporting checklist

Plate temperature, verification method, response criterion, and cutoff duration.
Trial count, inter-trial interval, baseline collection, and dose-to-test interval.
Whether latencies were raw, cutoff-clamped, averaged, or converted to percent maximum possible effect.
Observer blinding, video review rules, and treatment of ambiguous behaviors.
Companion controls for locomotion, sedation, body temperature, or motor impairment.
Species, strain, sex, age, body weight, housing, and acclimation conditions.

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.

Related workflow paths

Endpoint articles link to adjacent products, software workflows, and sibling endpoints where the connection is useful and already routable.

Hot plate latency calculator

Clamp trial latencies at a welfare cutoff and summarize animal-level hot plate data.

Pain percent maximum effect calculator

Convert baseline and post-drug latency into percent maximum possible effect when the design supports it.

Tail flick latency endpoint

Compare hot plate latency with a spinal reflex thermal endpoint.