Bertha Knoll

Differences in some behavioural effects of deprenyl and amphetamine enantiomers in rats

Effects of deprenyl and amphetamine enantiomers on different behavioural patterns were compared. Whereas (+)-amphetamine in doses of 1-3 mg/kg SC, (-)-amphetamine, and (+)-deprenyl in doses of 5-20 mg/kg SC increased the locomotor activity and the time the animals displayed stereotyped head movement, enhanced the acquisition of conditioned avoidance responses, and developed positive place preference conditioning, (-)-deprenyl, even in as high a dose as 20 mg/kg SC, failed to show any amphetamine-type behavioural effect. The results provide further proof why (-)-deprenyl, in contrast to other members of the amphetamine family, can be considered as a safe drug.

The anorectic effect of satietin is unrelated to carbohydrate metabolism

The effect of satietin and amphetamine on the carbohydrate metabolism of free fed and food deprived rats was studied. Rats deprived of food for 96 hours maintained normal glucose and glucagon blood levels but the blood concentration of insulin dropped from 232.02 +/- 23.93 to 12.48 +/- 0.71 pmol/l. Amphetamine (500 micrograms/animal, intracerebroventricularly) left in normally fed rats the blood concentration of glucose, insulin and glucagon unchanged. The same treatment, however, increased the insulin concentration in the blood of food deprived rats from 11.37 +/- 4.43 to 73.47 +/- 8.29 pmol/l. Glucose and glucagon, as well as insulin levels remained unchanged in both normally fed and food deprived rats when treated with satietin (20 micrograms/rat, intracerebroventricularly). It was concluded that the anorectic effect of satietin is unrelated to carbohydrate metabolism.

THE TYPE OF MAO IN THE NIGROSTRIATAL DOPAMINERGIC NEURONS OF THE RAT

Clorgyline, the selective inhibitor of MAO A counteracts the effect of the substantia nigra (SN) lesion, while (-)deprenyl, the selective inhibitor of MAO B proved to be ineffective showing that type A is the functionally important form of MAO in the nigrostriatal dopaminergic neurons of rat.

SATIETIN: A HIGHLY POTENT ANOREXOGENIC SUBSTANCE IN MAMMALIAN BLOOD

Publisher Summary This chapter focuses a substance named satietin that is capable of reducing food intake drastically in rats deprived of food for 96 h, which was discovered in human serum and detected in the blood of different species. Highly purified satietin samples extracted from human serum showing one band only in polyacrylamide gelelectrophoresis, containing in average 60.6% amino acids and 13.5% carbohydrates, were used for biological experiments. The intracerebroventricular injection of 10–100 μg satietin 5 h before the test meal decreased food consumption drastically and in a dose-dependent manner. The satietin-like long lasting inhibition of food intake seems to be unique.