A tail withdrawal procedure for assessing analgesic activity in rhesus monkeys

J Pharmacol Methods. 1986 Jun;15(3):263-9. doi: 10.1016/0160-5402(86)90056-2.


Rhesus monkeys were restrained in chairs from which their tails hung free so that their tails could be immersed into a thermos of water. Monkeys consistently kept their tails in 38-40 degrees C water for at least 20 sec, but withdrew them from 55 degrees C water in 1-4 sec. Tail withdrawal latencies from 55 degrees C water remained consistent over a period of 3 hr. Morphine produced dose-dependent increases in tail withdrawal latencies from 55 degrees C water, whereas pentobarbital, haloperidol, and phencyclidine did not increase tail withdrawal latencies except at doses that produced marked sedation.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Analgesics / pharmacology*
  • Animals
  • Dose-Response Relationship, Drug
  • Female
  • Haloperidol / pharmacology
  • Hot Temperature / adverse effects
  • Male
  • Morphine / pharmacology
  • Pain / drug therapy*
  • Pain / etiology
  • Pentobarbital / pharmacology
  • Phencyclidine / pharmacology
  • Reaction Time / drug effects


  • Analgesics
  • Morphine
  • Pentobarbital
  • Phencyclidine
  • Haloperidol