4-hydroxy-3-methoxy-acetophenone-mediated long-lasting memory recovery, hippocampal neuroprotection, and reduction of glial cell activation after transient global cerebral ischemia in rats.

4-Hydroxy-3-methoxy-acetophenone (apocynin) is a naturally occurring methoxy-substitute catechol that is isolated from the roots of Apocynin cannabinum (Canadian hemp) and Picrorhiza kurroa (Scrophulariaceae). It has been previously shown to have antioxidant and neuroprotective properties in several models of neurodegenerative disease, including cerebral ischemia. The present study investigates the effects of apocynin on transient global cerebral ischemia (TGCI)-induced retrograde memory deficits in rats. The protective effects of apocynin on neurodegeneration and the glial response to TGCI are also evaluated. Rats received a single intraperitoneal injection of apocynin (5 mg/kg) 30 min before TGCI and were tested 7, 14, and 21 days later in the eight-arm aversive radial maze (AvRM). After behavioral testing, the hippocampi were removed for histological evaluation. The present results confirm that TGCI causes memory impairment in the AvRM and that apocynin prevents these memory deficits and attenuates hippocampal neuronal death in a sustained way. Apocynin also decreases OX-42 and glial fibrillary acidic protein immunoreactivity induced by TGCI. These findings support the potential role of apocynin in preventing neurodegeneration and cognitive impairments following TGCI in rats. The long-term protective effects of apocynin may involve inhibition of the glial response.

Fish oil provides a sustained antiamnesic effect after acute, transient forebrain ischemia but not after chronic cerebral hypoperfusion in middle-aged rats.

We reported that fish oil (FO) abolishes retrograde amnesia consistently following transient global cerebral ischemia (TGCI) in young rats, provided it covered the first days prior to and after ischemia. Here, we further evaluated whether FO given post-ischemia in older rats (15-18 months old) is equally effective in facilitating memory recovery. We also tested whether the antiamnesic effect of FO observed after TGCI can be reproduced after chronic cerebral hypoperfusion (CCH). FO (300 mg/kg docosahexaenoic acid [DHA]) was delivered orally 4h after TGCI and continued once per day for 9 days. In the CCH group, FO treatment began soon after the first stage of 4-VO/ICA and continued daily for 43 days. Two weeks after surgery, the animals were tested for retrograde memory performance across 5 weeks. Both TGCI and CCH caused persistent memory impairment and hippocampal and cortical neurodegeneration. TGCI-induced retrograde amnesia was reversed by FO, an effect that was sustained for at least 5 weeks after discontinuing treatment. In contrast, the memory deficit caused by CCH remained unchanged after FO treatment. Both hippocampal and cortical damage was not alleviated by FO. We conclude that the FO-mediated antiamnesic effect following TGCI can be extended to older rats, even when the treatment begins 4h postischemia. Such efficacy was not reproduced after CCH. Therefore, the present results support the notion that FO may have therapeutic utility in treating learning/memory dysfunction after acute/transient cerebral ischemia and suggest that such benefits may not apply when a state of chronic cerebrovascular insufficiency is present.

Avaliação da atividade ansiolítica e antidepressiva do extrato fluido e fração aquosa de folhas de Passiflora alata Curtis em camundongos / Evaluation of anxiolytic and antidepressant activities in mice with fluid extracts and aqueous fraction obtained from the leaves of Passiflora alata

O extrato fluido (EF), preparado segundo a Farmacopéia Brasileira, e sua fração aquosa (FA) obtidos de folhas de Passiflora alata foram administrados por via oral em camundongos. Seus efeitos comportamentais foram avaliados por modelos que detectam a atividade ansiolítica e antidepressiva de drogas, tais como: o labirinto em cruz elevado (LCE) e o teste da suspensão pela cauda (TSC). Efeitos sobre a atividade locomotora geral dos animais foram monitorados no campo aberto. Efeitos sedativos foram observados com EF (100 e 300 mg kg-1) e EA (100, 300 e 600 mg kg-1), caracterizados por uma diminuição do número de entradas nos braços fechados do LCE e uma diminuição no número de cruzamentos e levantamentos no campo aberto. No TSC, a administração de EF (100 mg kg-1) ou FA (100 e 300 mg kg-1) resultou em aumento do tempo de imobilidade. Esses resultados são relevantes, pois contribuem para validar o uso popular dessa planta.

The fluid extract (FE), prepared according to the Brazilian Pharmacopoea, obtained from the leaves of Passiflora alata and its aqueous fraction (AF), were administered by oral route to mice, and the behavioural effects were evaluated using animal models that detect anxiolytic and antidepressant activities, such as the elevated plus maze (EPM) and the tail suspension test (TST). Effects on general motor activity were monitored in the open . Sedative effects were observed with FE (100 and 300 mg kg-1) and AF (100, 300 and 600 mg kg-1) and were characterized by a decreased number of entries in the enclosed arms of the EPM and a decrease in the number of crossings and rearing in the open . In the TST, FE (100 mg kg-1) and AF (100 and 300 mg kg-1) induced an increase in the immobility time. These results are relevant because they contribute to validate the traditional use of this plant.