title: Bacopa monnieri increases cerebral blood flow in rat independent of blood pressure.
abstract: Bacopa monnieri (L.) Wettst. (Brahmi in India and Thailand) is an ayurvedic dementia treatment, but its effect on cerebral blood flow (CBF) is still unknown. We sought to test its chronic and acute effects on CBF compared with Ginkgo biloba and donepezil. CBF was measured by laser Doppler from rat cerebral cortex after 8 weeks of daily oral dosing of these drugs. Systolic blood pressure was also measured using the tail cuff method or via arterial cannulation. In rats treated with B. monnieri (40 mg/kg), CBF was 25% increased [2927 ± 123 perfusion units, (PU)] compared with shams (2337 ± 217 PU, p < 0.05, nine rats). G. biloba (60 mg/kg) also increased CBF (by 29% to 3019 ± 208 PU, p < 0.05, nine rats). No clear effect was obtained with donepezil (1 mg/kg). Chronic administration of the preparations had no effect on blood pressure. In contrast, intravenous acute infusion of these herbals (20-60 mg/kg) had marked dose-dependent hypotensive actions (diastolic ~31 mmHg lower with 40 mg/kg of either extract), which correspondingly reduced CBF by ~15%. Likewise, CBF fell slightly with acute intravenous sodium nitroprusside and rose with noradrenaline. Donepezil (1 mg/kg) was slightly hypotensive without affecting CBF. Increased CBF with B. monnieri may account for its reported procognitive effect, and its further exploration as an alternative nootropic drug is worthwhile.
authors.affiliation: Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand.
authors.forename: Natakorn
authors.initials: N
authors.lastname: Kamkaew
authors.forename: C
authors.initials: C
authors.lastname: Norman Scholfield
authors.forename: Kornkanok
authors.initials: K
authors.lastname: Ingkaninan
authors.forename: Niwat
authors.initials: N
authors.lastname: Taepavarapruk
authors.forename: Krongkarn
authors.initials: K
authors.lastname: Chootip
mesh_terms: D000818:Animals; D034681:Bacopa / Q000737:chemistry*; D001794:Blood Pressure; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D000077265:Donepezil; D020441:Ginkgo biloba / Q000737:chemistry; D007189:Indans / Q000494:pharmacology; D008297:Male; D009599:Nitroprusside / Q000494:pharmacology; D018697:Nootropic Agents; D009638:Norepinephrine / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats
chemical_list: D007189:Indans; D018697:Nootropic Agents; D010880:Piperidines; D010936:Plant Extracts; D009599:Nitroprusside; D000077265:Donepezil; D009638:Norepinephrine