Brain-derived neurotrophic factor (BDNF) modulates inhibitory, but not excitatory, transmission in the CA1 region of the hippocampus

Brain-derived neurotrophic factor (BDNF) has been reported to have rapid effects on synaptic transmission in the hippocampus. We report here that bath application of BDNF causes a small but significant decrease in stimulus- evoked inhibitory postsynaptic currents (IPSCs) on CA1 pyramidal cells, which is prevented by the tyrosine kinase inhibitor lavendustin A. BDNF causes a decrease in the I/CV² of the IPSC, and also reduces paired-pulse depression of the IPSC, suggesting a presynaptic site of action. In contrast, BDNF did not have a detectable effect on field excitatory postsynaptic potentials measured in stratum radiatum. We conclude that BDNF has a selective depressant action on inhibitory transmission in the hippocampus, due at least in part to a presynaptic mechanism.