1. Comparison of intravenous and intranasal heroin self-administration by morphine-maintained humans

   • S. D. Comer
   • Eric D. Collins
   • Marian W. Fischman

   ORIGINAL INVESTIGATION Pages: 327 - 338

2. Naltrexone blockade of nicotine effects in cigarette smokers

   • L. H. Brauer
   • Frederique M. Behm
   • J. E. Rose

   ORIGINAL INVESTIGATION Pages: 339 - 346

3. Phenylalanine kinetics are associated with tardive dyskinesia in men but not in women

   • M. A. Richardson
   • Margaret A. Reilly
   • Istvan Sziraki

   ORIGINAL INVESTIGATION Pages: 347 - 357

4. Branched chain amino acids decrease tardive dyskinesia symptoms

   • M. A. Richardson
   • Margaret L. Bevans
   • Timothy J. Maher

   ORIGINAL INVESTIGATION Pages: 358 - 364

5. Opposite effects of 3,4-methylenedioxymethamphetamine (MDMA) on sensorimotor gating in rats versus healthy humans

   • F. X. Vollenweider
   • S. Remensberger
   • M. A. Geyer

   ORIGINAL INVESTIGATION Pages: 365 - 372

6. Residual effects of zolpidem 10 mg and zopiclone 7.5 mg versus flunitrazepam 1 mg and placebo on driving performance and ocular saccades

   • M. L. Bocca
   • F. Le Doze
   • P. Denise

   ORIGINAL INVESTIGATION Pages: 373 - 379

7. Relationships of plasma tryptophan availability to course of illness and clinical features of alcoholism: a preliminary study

   • Alan C. Swann
   • B. A. Johnson
   • Y. Richard Chen

   ORIGINAL INVESTIGATION Pages: 380 - 384

8. Rated well-being in relation to plasma concentrations of l- and d-methadone in satisfied and dissatisfied patients on methadone maintenance treatment

   • A. J. Hiltunen
   • O. Beck
   • S. Borg

   ORIGINAL INVESTIGATION Pages: 385 - 393

9. Effect of d-amphetamine on prepulse inhibition of the startle reflex in humans

   • K. E. Hutchison
   • Robert Swift

   ORIGINAL INVESTIGATION Pages: 394 - 400

10. In vitro immunoregulatory effects of lithium in healthy volunteers

    • M. Maes
    • C. Song
    • Eugene Bosmans

    ORIGINAL INVESTIGATION Pages: 401 - 407

11. Altered open-field behavior in experimental chronic hepatic encephalopathy after single venlafaxine and citalopram challenges

    • Gustav Apelqvist
    • Cecilia Wikell
    • Finn Bengtsson

    ORIGINAL INVESTIGATION Pages: 408 - 416

12. Cognitive performance in (±) 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”) users: a controlled study

    • U. D. McCann
    • Melissa Mertl
    • George A. Ricaurte

    ORIGINAL INVESTIGATION Pages: 417 - 425

13. The potentiating effect of sertraline and fluoxetine on amphetamine-induced locomotor activity is not mediated by serotonin

    • T. L. Sills
    • A. J. Greenshaw
    • P. J. Fletcher

    ORIGINAL INVESTIGATION Pages: 426 - 432

14. Resolution of treatment-refractory depression with naltrexone augmentation of paroxetine – a case report

    • Revital Amiaz
    • Orit Stein
    • S. Schreiber

    LETTER TO THE EDITORS Pages: 433 - 434