Pathogenesis of atherosclerosis: I: Role of the nervous system.

The new method of lateral carotid artery original-location autograft was used in the present study. An animal model was prepared with which to investigate the neurogenic role in the pathogenesis of atherosclerosis. Two experiments were performed in 16 operated rabbits to whom was fed a cholesterol-rich diet for four months. In the first experiment, the expected results were obtained in 9 rabbits. Significant atherosclerotic plaques were observed in 4 of 9 (44.4%) samples of intact carotid artery; lipid deposition was found in another 3 (33.3%) samples in which atherosclerotic plaques were not observed by the naked eye but were exhibited by light microscopy; negative results were shown only in 2 (22.2%) samples both by the naked eye and by light microscopy. However, atherosclerotic plaques were found only in autograft anastomoses but not within the segment of carotid artery autograft. Then, a second experiment as performed with 7 operated rabbits, and similar results were obtained. These results clearly indicate that the nervous system plays a very important role in the pathogenesis of atherosclerosis.

[Effects of (-), (+) clausenamide on central N-methyl-D-asparate receptors in rodents].

Using radioligand binding assay, the effects of (-), (+) clausenamide on N-methyl-D-asparate(NMDA) receptor were studied in synaptic membrane, hippocampus and cerebral cortex in rats. The Bmax and KD values of NMDA receptor in mouse brain were measured with Scatchard plot method. Results showed that there was no specific binding of (-), (+) clausenamide to NMDA-receptor. However, higher Bmax values were observed in (-) clausenamide-treated rats than the control group, but no effect on KD value. (+) Clausenamide treatment showed no effect on Bmax and KD values. The findings suggest that the pharmacologic actions of clausenamide depends on its chirality. Up regulation of NMDA-receptor induced by (-) clausenamide is helpful to elucidate its nootropic mechanism.

[Determination of acetylcholine by high performance liquid chromatography, enzyme-loaded postcolumn, and electrochemical detector].

A rapid and simple method using a combination of high performance liquid chromatography (HPLC), an immobilized enzyme column, with electrochemical detection (ECD) is described for the assay of acetylcholine (ACh) and choline (Ch) in mouse brain. Perchloric acid extracts of small brain tissue were injected onto the HPLC system with no preclean-up procedure Detection limits for both compounds were 1 pmol. The present method has been successfully applied to the measurement of ACh in discrete brain areas of the mouse.

Stimulation of central cholinergic neurons by (-)clausenamide in vitro.

AIM: To study the neurotrophic effects of (-) and (+)clausenamide on frontal cortex neurons in culture. METHODS: The activity of the choline acetyltransferase (ChAT) was determined by spectrophotometric method; protein content was assayed by Folin phenol method. RESULTS: (-)Clausenamide increased the activity of ChAT and protein content in cultured neurons, as well as stimulated proliferation of neuronal cells, support survival and neurite outgrowth of neurons. The neurotrophic action of (-)clausenamide (0.001-10 mumol.L-1) was similar to that of nerve growth factor. The (+)clausenamide had no neurotrophic action, even at high concentrations (0.1-10 mumol.L-1), but neurons were damaged. CONCLUSION: (-)Clausenamide stimulated central cholinergic neuron development.

Effects of methylflavonolamine on free intracellular calcium in isolated embryonic rat brain cells.

AIM: To observe the effects of methylflavonolamine (MFA) on free intracellular calcium concentration ([Ca2+]i) of isolated embryonic rat brain cells in presence and absence of high extracellular potassium and L-glutamate. METHODS: [Ca2+]i was measured in a spectrofluorophotometer by preloading the cells with calcium sensitive fluorescent indicator Fura 2-AM. RESULTS: Resting [Ca2+]i was 197 +/- 20 nmol.L-1 (n = 44) in the presence of Ca2+ 1.3 mmol.L-1 in Hanks' solution. MFA 0.15 mmol.L-1 had no effect on the resting [Ca2+]i. When extracellular Ca2+ was 1.3 mmol.L-1, MFA (0.03-0.3 mmol.L-1) concentration-dependently inhibited the [Ca2+]i elevation induced by high extracellular potassium, with an IC50 value of 0.14 (95% confidence limits: 0.05-0.42) mmol.L-1. At higher concentration (0.15-0.30 mmol.L-1), MFA decreased L-glutamate-induced [Ca2+]i elevation, with an IC50 of 0.20 (95% confidence limits: 0.01-3.40) mmol.L-1. CONCLUSION: MFA inhibited Ca2+ influx through voltage-dependent calcium channel and, at higher concentration, through receptor-operated calcium channel in the embryonic rat brain cells.