[1] SWEDISH UNIV AGR SCI, DEPT PHYSIOL, S-75007 UPPSALA, SWEDEN
[2] UNIV UPPSALA, DEPT PHARMACOL, S-75105 UPPSALA, SWEDEN
[3] UNIV MINNESOTA, DEPT ANAT, MINNEAPOLIS, MN 55455 USA
[4] NYU, MED CTR, DEPT PSYCHIAT, NEW YORK, NY 10003 USA
[5] UNIV TEXAS, HLTH SCI CTR, DEPT INTERNAL MED, DALLAS, TX 75235 USA
[6] UNIV TEXAS, HLTH SCI CTR, DEPT PHARMACOL, DALLAS, TX 75235 USA