SAFFRON EXTRACT AND TRANS-CROCETIN INHIBIT GLUTAMATERGIC SYNAPTIC TRANSMISSION IN RAT CORTICAL BRAIN SLICES

Saffron, the dried stigmata of Crocus sativus L., is used in traditional medicine for a wide range of indications including cramps, asthma, and depression. To investigate the influence of hydro-ethanolic saffron extract (CSE) and trans-crocetin on synaptic transmission, postsynaptic potentials (PSPs) were elicited by focal electrical stimulation and recorded using intracellular placed microelectrodes in pyramidal cells from rat cingulate cortex. CSE (10-200 mu g/ml) inhibited evoked PSPs as well as the isolated NMDA and non-NMDA component of PSPs. Glutamate (500 mu M) added into the organ bath induced membrane depolarization. CSE decreased glutamate-induced membrane depolarization. Additionally, CSE at 100 mu g/ml decreased NMDA (20 mu M) and kainate (1 mu M)-induced depolarization, whereas AMPA (1 mu M)-induced depolarization was not affected. Trans-crocetin (1-50 mu M) showed inhibition of evoked PSPs and glutamate-induced membrane depolarization comparable to CSE. Trans-crocetin at 10 mu M decreased NMDA (20 mu M)-induced membrane depolarization, but did not inhibit the isolated non-NMDA component of PSPs. We conclude that trans-crocetin is involved in the antagonistic effect of CSE on NMDA but not on kainate receptors. (C) 2011 IBRO. Published by Elsevier Ltd. All rights reserved.