A Brain Imaging Study of Opioid (Morphine) and Non-opioid (Ketorolac) Conditioning Effects

Inclusion Criteria: 1. Healthy male and female adults, aged 21-50 2. No contraindications to fMRI scanning 3. Within 15% of normal BMI 4. Right handed (dominant hand is right hand) 5. Have taken an opioid drug at least once in the past (for example, after a surgery) Exclusion Criteria: 1. Current or past history of major medical, neurological, or psychiatric illness 2. Women who are pregnant or breast feeding, have gone through menopause, or have irregular menstrual cycles (length of cycle must be within 26 to 32 days) 3. Contraindications to morphine administration: * i) Hypersensitivity to morphine or other phenanthrene-derivative opioid agonists (codeine, oxycodone, etc.), morphine salts, or any component of the product * ii) Concomitant use of other CNS depressants including antihistamines or alcohol * iii) History of drug or alcohol abuse * iv) History of head trauma * v) History of liver problems * vi) Pre-existing respiratory conditions (ex. COPD, asthma) * vii) Current use of any drugs that interact with morphine 4. Contraindications to ketorolac administration * i) Allergic-type reaction, or urticaria in response to exposure to aspirin or other NSAIDS * ii) Concomitant aspirin or NSAID use * iii) Hypersensitivity previously demonstrated to ketorolac tromethamine or to any product component * iv) Peptic ulcer disease (active or history), or other gastrointestinal problems * vi) Current use of any drugs that interact with ketorolac (ex. heparin/warfarin) * vii) History of bleeding disorder * viii) Low body weight, under 50 kg 5. Contraindications to fMRI scanning (including cardiac pacemaker, metal implants, claustrophobia, pregnancy) 6. Contraindications to either of the emergency medications (Ondansetron or Narcan) 7. History of head trauma 8. High blood pressure (\>140 systolic, \>90 diastolic) 9. History of impaired urinary elimination 10. Major kidney problems, bleeding problems, severe dehydration, or recovering from a recent surgery (within past year). 11. Instability of responses to experimental pain (see Study Procedures Section) 12. History of asthma 13. History of diabetes 14. Liver Function Test results greater than 2.5 times the upper limit of normal (ULN) at Screening 15. History of smoking (past or current) 16. Use of psychotropic drugs, hormone treatments (including hormonal birth control) within 1 year 17. Non-fluent speaker of English 18. Positive urine drug screen (i.e. positive on any of the 10 measures tested, including cocaine, marijuana, opiates, amphetamines, methamphetamines, phencyclidine, barbiturates, benzodiazepines, methadone, and tricyclic antidepressants)