Effects of the blood components on the AMPA and NMDA synaptic responses in brain slices in the onset of hemorrhagic stroke.

Blood-borne events play a major role in post bleeding disturbances of the neuronal network. However, very little is known about the early effects of blood plasma, leucocytes, and the red blood cells on the AMPA and NMDA-mediated synaptic responses in the onset of experimental intracranial hemorrhage (ICH). In this study, we used the technique of on-line monitoring of electrophysiological parameters referred to synaptic activity in piriform cortex of SHR rat slice. We exposed the olfactory cortex slices to diluted autologous blood or its components and compared with effects of ferric chloride. Whole blood exerted a total inhibition of synaptic activity in piriform cortex within first 5 min. Dilution of blood induced prolonged epileptic synaptic activation of NMDA receptors. Blood plasma and fraction of leucocytes induced hyperactivation of neurons transforming to epileptiform discharges. Fraction of red blood cells acted biphasic, an initial sharp activity of AMPA- and NMDA-mediated receptors replaced by a following total depression. Our slice-based models of experimental stroke revealed the mechanism of the earliest pathophysiologic events occur in brain tissue during bleeding that may be relevant to the human ICH.