5.3.4. Monkey-shock titration test

This model carries monkeys as animal model and kept them in restraining chairs. The monkey shock titration is a final evaluation of a new compound before administration to man. Electrical current is conveyed by a Coulbourn Instrument programmable stunner through cathodes coupled to two test tube clasps, which are connected to a shaved bit of the tail. The current ranges from 0 to 4 mA through 29 progressive steps. This current is suppressed by a bar pressed by monkey. On the day before the drug administration, a stable baseline shock level is recognized for each monkey. Drugs in different doses like 3.0 mg/kg i.m. morphine, 1.7 mg/kg i.m. methadone, and 10 mg/kg i.m. pentazocine were used. However, this test is time consuming [73].

#### 5.3.5. Stimulation of the limbs

For pharmacological studies of analgesia, electromyographic recordings of nociceptive limb reflexes have been used for, but they are far less common than behavioural tests. These electromyographic studies have permitted the measurement of reactions paying little heed to whether there is any development.
