Effects of (-), (+)-7-hydroxy-clausenamide on synaptic transmission in rat dentate gyrus in vivo

AimTo investigate effects of (-), (+)-7-hydroxy-clausenamide (7-OH-Clau) on basal synaptic transmission in the dentate gyrus of anesthetized rats. MethodsExtracellular recording of the population spike (PS) of hippocampal dentate gyrus following application of low-frequency stimulation (1/30 Hz, 1.0 mA). ResultsFifteen, thirty and sixty minutes after intracerebroventricular (icv) administration of an estimated final brain concentration of 2×10_-6 mol·L^-1, (-)-7-OH-Clau caused over 30% increase relative to basal PS amplitude before administration, and 27%-41% increase relative to vehicle control (P<0.05), while (+)-7-OH-Clau exhibited 18%-25% and 11%-20% decrease in the PS amplitude when compared with basal PS amplitude and vehicle control (P<0.05), respectively. ConclusionThe basal synaptic transmission in the dentate gyrus of the rat hippocampus can be potentiated by (-)-7-OH-Clau and attenuated by (+)-7-OH-Clau, indicating that there was a stereoselective difference between the two enantiomers in the modulation of synaptic responses and plasticity.