RESUMO
To investigate the exact mechanism of epileptogenesis induced by coriaria lactone (CL), the effect of CL on NMDA receptor mediated current (Iasp) in rat hippocampal CAI neurons was investigated by using nystatin perforated whole-cell patch clamp. 10-6-10-4 mol/L Asp acted on NMDA receptors and elicited an inward current (Iasp) at a holding potential (VH) of -40mV in presence of 10-6 mol/L glycine and absence of Mg2+ extracellularly. CL enhanced NMDA receptor mediated current induced by Asp, but had no effect on threshold concentration, EC50,Hill coefficient as well as maximal-effect concentration and reversal potential of Iasp. The effect had no relationship with holding potential. These results showed that CL could enhance NMDA receptor mediated current to increase [Ca2+]I of neurons by acting on Gly site, thereby inducing epilepsy.
RESUMO
To investigate the exact mechanism of epileptogenesis induced by coriaria lactone (CL), the effect of CL on NMDA receptor mediated current (Iasp) in rat hippocampal CAI neurons was investigated by using nystatin perforated whole-cell patch clamp. 10-6-10-4 mol/L Asp acted on NMDA receptors and elicited an inward current (Iasp) at a holding potential (VH) of -40mV in presence of 10-6 mol/L glycine and absence of Mg2+ extracellularly. CL enhanced NMDA receptor mediated current induced by Asp, but had no effect on threshold concentration, EC50,Hill coefficient as well as maximal-effect concentration and reversal potential of Iasp. The effect had no relationship with holding potential. These results showed that CL could enhance NMDA receptor mediated current to increase [Ca2+]I of neurons by acting on Gly site, thereby inducing epilepsy.
RESUMO
Molecular cloning of cDNAs coding for ligand-gated ion channel subunits makes it possible to study the pharmacology of recombinant receptors with defined subunit compositions. Many laboratories have used these techniques recently to study actions of agents that produce general anesthesia. Most of the volatile and intravenous anesthetics potentiate the function of GABAA receptor to different extent. Glycine, AMPA, kainate,NMDA, and 5-HT3 recepors are also the targets for many anesthetics. Subunit specific actions of some of the agents suggest that construction and testing of certain chimeric receptor subunits may be useful for defining the amino acid sequences responsible for anesthetic actions.