Comparison of the effect of TAK-147 (zanapezil) and E-2020 (donepezil) on extracellular acetylcholine level and blood flow in the ventral hippocampus of freely moving rats
| Autor: | Arai Takashi, Katsunori Iwasaki, Izzettin Hatip-Al-Khatib, Nobuaki Egashira, Michihiro Fujiwara |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2004 |
| Předmět: |
Male
zanepezil hippocampus Acetylcholine/*metabolism Animals Benzazepines/*pharmacology Donepezil Dose-Response Relationship Drug Extracellular Fluid/drug effects/metabolism Hippocampus/*blood supply/*drug effects/metabolism Indans/*pharmacology Piperidines/*pharmacology Rats Rats Wistar data analysis Hemodynamics animal cell gnawing fasciculation Fasciculation Piperidines blood flow rat Chemistry General Neuroscience article Alzheimer's disease laser Doppler flowmetry salivation donepezil Dose–response relationship priority journal Indans medicine.symptom Acetylcholine drug potency medicine.drug medicine.medical_specialty Microdialysis high performance liquid chromatography microdialysis animal experiment Zanapezil Ventral hippocampus E2020 Neurotransmitters modulators transporters and receptors defecation animal tissue Internal medicine medicine Potency controlled study skeletal muscle Molecular Biology nonhuman Extracellular Fluid Blood flow Benzazepines acetylcholine Endocrinology Neurology (clinical) Developmental Biology |
| Popis: | The effects of zanapezil (TAK-147) and donepezil (E2020) on extracellular acetylcholine (ACh) levels were investigated by HPLC-microdialysis of ventral hippocampus (VH) in freely moving intact rats. The results showed that the basal ACh release rate in the VH is 116.7±12.4 to 158.4±22.86 fmol/20 µl. At 2, 5 and 10 mg/kg, single p.o., each drug increased ACh level by 9.4%, 106.5%, 50.8% (TAK-147) and 14.8%, 76.1%, 120.94% (E2020), respectively. The ED50 values were 4.52 mg/kg (1.43-14.29; R=0.52) and 4.07 mg/kg (1.77-9.37; R=0.985) for TAK-147 and E2020, respectively. Analysis of data revealed that the relative TAK-147/E2020 potency ratio is 0.773, but the effect of E2020 was accompanied by more prominent skeletal muscle fasciculation, gnawing, increased defecation and to lesser extent salivation. Moreover, the significant effect of TAK-147 was observed earlier (20 min) than E2020 (60 min). In this study, we also investigated the effect of both drugs at dose of 5 mg/kg p.o. on blood flow in the VH using Laser Doppler Flowmetry. The results showed that the average blood flow rate in the VH is 6.5±0.9 ml/min/100 g. TAK-147 did not change blood flow, but E2020 increased blood flow in a biphasic manner. The first increment was obtained between 5 and 40 min (11.5±2.2 to 12.7±2.2 ml/min/100 g), and the second one 80-105 min (10.7±1.6 to 13.4±3.6 ml/min/100 g). In conclusion, the present results indicate that both TAK-147 and E2020 increase ACh level in the VH. E2020 showed greater potency than TAK-147, but it induced more fasciculation and other side effects than TAK-147. Moreover, the blood flow increasing properties of E2020 could be beneficial in some patients with Alzheimer' disease especially those with chronic vascular dementia, but at the same time, it could also indicate less specific ACh increasing activity than TAK-147 and higher risk of cerebral hemorrhage. On the other hand, the fast and specific effect of TAK-147 may be useful for cure of early stages of Alzheimer's disease (AD). © 2004 Elsevier B.V. All rights reserved. |
| Databáze: | OpenAIRE |
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