5-Hydroxytryptamine-containing (5-HT) neurones in brain of the mouse were selectively destroyed by intracerebroventricular injection of 5,7-dihydroxytryptamine (5,7-DHT, 50 micrograms). Sham-lesioned controls received vehicle (2 microliters, i.c.v.). Two weeks later the head-twitch response induced by 5-methoxy-N,N-dimethyltryptamine (2.0 mg/kg) and… (More)
Platelet serotonin (5-HT) concentration did not significantly differ between control subjects (N = 45) and schizophrenic (N = 62) or chronic schizophrenic (N = 39) patients. No clinical feature was associated with hyperserotonemia, but the subgroup receiving benzodiazepines had a significantly higher 5-HT level than other patients.
The effects of a single (15 mg) dose of diazepam, a 3-week course of diazepam (25 mg/d) and its withdrawal on plasma MHPG and the reduction produced by clonidine (1.5 micrograms kg-1 i.v.) were studied in 8 male volunteers. Chronic diagram reduced, but not significantly, plasma MHPG and attenuated the reduction produced Gyclonidine. During the withdrawal… (More)
The reports of hyperserotonaemia in chronic schizophrenics and the indications that fenfluramine, a serotonin-releasing drug, may be of therapeutic value in hyperserotonaemic autistic children, were the rationale for this clinical trial. Fenfluramine was administered to 4 treatment-resistant chronic schizophrenic in-patients. They were studied for 14 weeks:… (More)
The effect of the alpha 2-adrenoceptor agonist clonidine on plasma free MHPG levels was assessed in 12 normal volunteers. A significant fall in MHPG was produced by 1.5 microgram X kg-1 clonidine IV whereas saline had no effect. The peak fall in MHPG correlated strongly with the area under the curve (AUC). In addition, a strong correlation was seen between… (More)
Small doses of clonidine produce hypoactivity in mice and rats, probably by stimulating pre-synaptic alpha 2-adrenoceptors in the brain. When mice were injected with desmethylimipramine (DMI, 5 mg/kg) before clonidine it attenuated the hypoactivity, while pretreatment with amitriptyline (5 mg/kg) or mianserin (5 mg/kg) potentiated this behaviour. In rats,… (More)