Search

Desoxyfructo-serotonin oxalate and free base produced a decrease of the blood pressure and heart rate of vagotomized cats (in total doses of 100 mg, i.v.) for 30 and 120 min. respectively, with total blocking of the carotid occlusion pressor response. With desoxyfructo-5-methoxytryptamine the decrease in the blood pressure lasts only 1 minute, followed by a 30 min. moderate increase. With this compound the C.O. pressor response is not blocked. On anaesthetized dogs with opened thorax low doses of the drug (100–200 μg/kg i.v.) produced a similar decrease of the blood pressure and heart rate, however, only for a short time (3 min.). An important increase in the sinusal coronary flow and partial oxygen pressure was also observed. Oral administration of desoxyfructo-serotonin oxalate (50 mg/kg) reduced to 40% the gastric ulcer formation by restraint in rats. With the same compound (100 mg/kg i.p. daily per 4 days) a very significant “anti-stress” activity was observed on mice by increased swimming endurance, Rota-Rod test performance, anti-ulcer effect and by elimination of milk induced leucocytosis.

At concentrations less than 10 −5 Moles, desoxyfructoserotonin oxalate has very little direct effect on human blood platelets, but still interferes with the active transport and release of serotonin.

Desoxyribulo-serotonin shows a serotonin-like activity on both D and M type tryptaminergic receptors. Similarly to desoxyfructo-serotonin, its affinity is about 100 times less towards these receptors when compared to serotonin. The intrinsic activities of the two sugar derivatives for D type receptors are nearly equal and very close to the initial value of serotonin. Desoxyfructo-serotonin showed a decreased intrinsic activity for M type receptors with 70 % of the initial value observed for serotonin. The intrinsic activity of desoxyribulo-serotonin for these receptors is even less, showing only 40 % activity. The effect of desoxyribulo-serotonin on platelet functions is revealing : in spite of its decreased intrinsic activity towards M type receptors, the ribose derivative shows unchanged or higher activities in shape-change, aggregation, inhibition of the uptake and the release of serotonin, than desoxyfructo-serotonin, confirming earlier observation, that M type receptors are not involved in platelet functions. It is noteworthy that desoxyribulo-serotonin is a nearly total inhibitor of the release of serotonin from platelets induced by 5,6-dihydroxytryptamine.

Desoxyfructo-serotonin is a new synthetic sugar derivative of serotonin, however, its formation in physiological conditions can also be expected. Using rat brain monoamine oxidase (MAO) in vitro , desoxyfructo-serotonin is significantly more slowly metabolized than serotonin. “Transcypromine”, a specific inhibitor of MAO, also inhibits the oxidative deamination of the sugar derivative.