Serotonin activates adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] of NCB-20 neuroblastoma--brain hybrid cells with an activation constant of 530 nM, but has little or no effect on cellular cyclic AMP or cyclic GMP content of NIE-115 neuroblastoma or NG108-15 hybrid cells. In homogenates of NCB-20 hybrid cells, lysergic acid diethylamide stimulates adenylate cyclase activit...

Serotonin increases the level of cyclic AMP in incubated rabbit corneas; the concentration of agonist producing half-maximal stimulation is approximately 1.5 microM. Nialamide, an inhibitor of monoamine oxidase, potentiates the response to serotonin but not to epinephrine. Amitriptyline, an inhibitor of neuronal uptake of serotonin, does not potentiate the stimulation of cyclic AMP synthesis. L...

Several antagonistic interactions between morphine and LSD-25 (lysergic acid diethylamide) have been demonstrated. LSD-25 antagonizes morphine induced analgesia in rats (1) and emesis in dogs (2). It also blocks the miotic action of morphine (3). On the other hand morphine blocks LSD-25 induced pyre xia in rabbits (4) and the central hypotensive effect of LSD-25 in dogs (5). Morphine produces m...

Although lysergic acid diethylamide (LSD), the hallucinogenic agent, has been the subject of numerous investigations, little is known about its biologic fate. In recent studies Boyd et al.’ and St011 el ~1.2 have examined the tissue distribution of CL4-labeled LSD in mice. Stoll and his co-workers2 have shown that the Cr4-labeled material measured in tissues included LSD, as well as transformat...