dihydroergotoxine and vindeburnol

The effects of a new eburnamenine derivative (3 beta,14 alpha, 16 alpha)-(+/-)-14,15-dihydro-20,21-dinoreburnamenin-14-ol (vindeburnol, RU 24722) on EEG, on brain energy metabolism and on local cerebral blood flow (LCBF) and in different experimental models of cerebral insufficiency were compared with those of vincamine, vinburnine (1-eburnamonine), dihydroergotoxine mesilate and nicergoline. Vindeburnol at 2 mg/kg i.v., increased the EEG resistance time in rats subjected to asphyxia anoxia and at 10 mg/kg s.c., significantly improved the electrocortical recovery of gerbils subjected to a 10-min cerebral ischemia. Vindeburnol (10 mg/kg i.p.) significantly retarded glucose, phosphocreatine and adenosine triphosphate utilization and lactate production in mouse brain during 10 s of decapitation ischemia. The cerebral metabolic rate was 10.34 mmol/kg/min, which was about 50% of the control value. At 10 mg/kg i.p., the product induced a slight and transient increase in LCBF. Vincamine improved the early phase of the postischemic electrocortical recovery in the gerbil, had no effect on cerebral energy substrates and slightly increased the LCBF for 15 min. Dihydroergotoxine mesilate improved the early phase of the electrocortical recovery in gerbils subjected to ischemia, did not significantly modify the energy substrates and rapidly increased the LCBF, which was normal after 30 min. Vinburnine and nicergoline were inactive in the cerebral insufficiency models used and did not significantly modify cerebral energy metabolism. These results show that vindeburnol has a different pharmacological profile from vincamine, vinburnine, dihydroergotoxine mesilate and nicergoline, and suggest that vindeburnol may be therapeutically effective in cerebral insufficiency.

Topics: Animals; Brain Ischemia; Cerebral Cortex; Cerebrovascular Circulation; Cerebrovascular Disorders; Dihydroergotoxine; Electroencephalography; Ergolines; Gerbillinae; Male; Mice; Mice, Inbred Strains; Nicergoline; Rats; Rats, Inbred Strains; Vinca Alkaloids; Vincamine

The influence of a new eburnamenine derivative RU 24722 [(3 beta, 14 alpha, 16 alpha)-(+/-)-14,15-dihydro-20,21-dinoreburnamenin -14-ol] on post-ischemic EEG recovery was studied in N2O anesthetized rats subjected to 1 min of global-compression cerebral ischemia. RU 24722 was compared with vincamine, dihydroergotoxine mesylate and nicergoline. Treatment with RU 24722 (2 mg/kg i.v.) significantly decreased the EEG recovery time and increased the electrocortical activity during the first phase of the post-ischemic recovery. Vincamine (2 mg/kg i.v.), dihydroergotoxine mesylate (0.5 mg/kg i.v.) and nicergoline (0.5 mg/kg i.v.) were devoid of activity. In an attempt to elucidate its mechanism of action, the influence of RU 24722 on changes in the cerebral metabolic energy reserves was studied in mouse brain after different periods of decapitation ischemia. The changes occurring during the first 10 s of ischemia were used to calculate the baseline cerebral metabolic rate (CMR). The activity of RU 24722 was compared with that of vincamine and pentobarbital. RU 24722 (10 mg/kg i.p.) significantly retarded glucose, phosphocreatine and adenosine triphosphate utilisation and lactate production. Vincamine (10 mg/kg i.p.) had no effect on cerebral energy substrates. Pentobarbital (100 mg/kg i.p.) markedly increased the tissue concentration of glucose and phosphocreatine and decreased lactate levels before and after ischemia. The improvement of EEG recovery suggests that RU 24722 may be therapeutically effective in cerebral insufficiency, and the decreased brain energy demand may be one of the mechanisms by which RU 24722 has a protective effect against cerebral ischemic damage.

Topics: Adenosine Triphosphate; Animals; Brain; Brain Ischemia; Dihydroergotoxine; Electroencephalography; Energy Metabolism; Glucose; Glycogen; Lactates; Lactic Acid; Male; Mice; Nicergoline; Phosphocreatine; Rats; Vasodilator Agents; Vinca Alkaloids; Vincamine