Converging Effects ofGinkgo bilobaExtract at the Level of Transmitter Release, NMDA and Sodium Currents and Dendritic Spikes

Abstract

In this study, an attempt was made to integrate the effects of GINKGO BILOBA extract (GBE) in different experimental systems (IN VITRO cochlea, brain slice preparations and cortical cell culture) to elucidate whether these processes converge to promote neuroprotection or interfere with normal neural function. GBE increased the release of dopamine in the cochlea. NMDA-evoked currents were dose-dependently inhibited by rapid GBE application in cultured cortical cells. GBE moderately inhibited Na+ channels at depolarised holding potential in cortical cells. These inhibitory effects by GBE may sufficiently contribute to the prevention of excitotoxic damage in neurons. However, these channels also interact with memory formation at the cellular level. The lack of effect by GBE on dendritic spike initiation in neocortical layer 5 pyramidal neurons indicates that the integrative functions may remain intact during the inhibitory actions of GBE.

TheGinkgo bilobaextract EGb 761®and its main constituent flavonoids and ginkgolides increase extracellular dopamine levels in the rat prefrontal cortex

“…Several studies have indicated that G. biloba extracts may affect the brain dopamine system and dopamine-mediated functions (Shah et al, 2003;Szasz et al, 2008;Yeh et al, 2008;Fehske et al, 2009). However, this is the first report linking the effects of EGb 761 to the PFC, that is, the brain area that is neuroanatomically relevant to learning and memory processing.…”

“…Several studies have indicated that G. biloba extracts may affect the brain dopamine system and dopamine‐mediated functions (Shah et al. , 2003; Szasz et al. , 2008; Yeh et al.…”

Inhibition of cPLA2 activation by Ginkgo biloba extract protects spinal cord neurons from glutamate excitotoxicity and oxidative stress‐induced cell death

“…EGb761 was also shown to reduce neuronal death in global brain ischemia and Glu‐induced excitotoxicity (Chandrasekaran et al. 2002), and inhibit NMDA receptor‐mediated calcium influx and neuronal death (Szasz et al. 2008; Shi et al.…”

Retrospect and prospect of active principles from Chinese herbs in the treatment of dementia

“…The protective effects of EGb761 were shown in in vitro injury models induced by hypoxia, hydrogen peroxide, glutamate, verapamil, Aβ and nitric oxide (NO) [52] , as well as in an in vivo model induced by ischemia [53,54] . The purported biological effects of EGb761 include amelioration of mitochondrial dysfunction [55] , blockade of the NMDA receptor [56,57] , scavenging of free radicals, lowering of oxidative stress, reduction of neural damages, reduction of platelet aggregation, antiinflammation [58] and anti-aging [59] . Clinically, EGb761 has been prescribed to treat central nervous system (CNS) disorders such as AD and cognitive deficits, which may be attributed to the aforementioned effects.…”