[Effect of 4-(o-benzylphenoxy)-N-methylbutylamine hydrochloride (bifemelane hydrochloride, MCI-2016) on cerebral glucose metabolism]

Effects of bifemelane on muscarinic receptors and choline acetyltransferase in the brains of aged rats following chronic cerebral hypoperfusion induced by permanent occlusion of bilateral carotid arteries

Cerebral hypoperfusion was chronically induced in aged rats via permanent bilateral occlusion of common carotid arteries (2VO). Marked reduction of the Bmax value of the muscarinic receptors (mAChR) in both the cortex and striatum and the Vmax value of choline acetyltransferase (ChAT) activity in the cortex, hippocampus and striatum were observed as compared with those of control aged rats. No significant changes in mAChR and ChAT activity were observed between young control rats and young 2VO rats. One month post-surgery in aged rats, daily doses of bifemelane (10 mg/kg) or aniracetam (50 mg/kg) were administered orally over a 4-week period. Administration of bifemelane significantly increased Bmax values and decreased apparent Kd values for 3H-quinuclidinyl benzilate (QNB) in mAChR in the striatum. Chronic administration of bifemelane or aniracetam also enhanced ChAT activity in the cortex, hippocampus and striatum. In particular, administration of bifemelane resulted in a significant increase in Vmax values of ChAT in all three brain regions, while no significant change in K(m) values for ChAT was observed. These results suggest that bifemelane is responsible for this activity, thereby enhancing the functioning system of CNS cholinergic neurons of cerebral hypoperfused aged rats.

Protective effect of bifemelane on c-Fos-like immunoreactivity in rat cerebral ischemia

Cytoprotection by bifemelane hydrochloride was investigated immunohistochemically in the cerebral cortex of rats during ischemia. The middle cerebral artery was occluded for 30 min and then reperfused for 6 h. c-Fos-like immunoreactive neurons were found in layers II to VI of the cerebral cortex and were especially abundant in the parietal cortex and the piriform cortex on the side of the occlusion. In sham-operated control rats, a few c-Fos-like immunoreactive neurons were seen in the ipsilateral side of the cerebral cortex. In animals that had been injected with bifemelane hydrochloride (20 mg/kg, IP) 30 min before the onset of ischemia and 90 min after reperfusion, the number of c-Fos-like immunoreactive neurons was significantly reduced in the cerebral cortex. The results suggest that bifemelane hydrochloride can inhibit the ischemia-induced increase in c-Fos-like immunoreactivity in cerebral cortex neurons.

Effects of bifemelane on calcium and magnesium deposition in the central nervous system tissues of rats maintained on low-calcium diets

The effects of bifemelane [4-(o-benzylphenoxy)-N-methylbutylamine hydrochloride] on the deposition of calcium and magnesium in central nervous system (CNS) tissues, heart, liver, kidney, muscle, abdominal aorta and bones were studied in rats maintained on standard and low-calcium diets. Rats were maintained for 90 days on the following diets: standard calcium (12.5 g/kg diet); standard with 100 mg/kg bifemelane; low-calcium (30 mg/kg diet); and low-calcium with bifemelane. The presence of bifemelane did not affect blood chemistry, but the magnesium concentration in the cerebellum was significantly (P less than 0.05) higher in rats receiving standard diet after bifemelane treatment. Magnesium concentrations in the pons, cerebellum, spinal cord, heart, liver and femur of bifemelane-treated rats fed low-calcium diets were significantly (P less than 0.05) higher compared with the corresponding controls, whereas the calcium concentration in the liver was significantly (P less than 0.05) lower. In general, bifemelane tended to decrease calcium deposition in the CNS and soft tissues of rats fed standard or low-calcium diets. Bifemelane may activate cerebral metabolism and maintain magnesium concentrations in the CNS and soft tissues, and be implicated in metal metabolism in rats fed low-calcium diets.