Abstract: AIM: To study the effects of propofol on long-term potentiation (LTP) in the CA1 area of rat hippocampus in vivo and to elucidate the possible underlying mechanisms. METHODS: 63 pentobarbitone-anaesthetized rats were used to investigate the effects of propofol (20 mg/kg, i. p.) alone and with NMDA or AMPA receptor antagonists (APV or CNQX) on excitatory postsynaptic potential (EPSP) and LTP expression of the CA1 stratum radiatum of the rat hippocampus by using stereotaxic technology and extracellular recording. RESULTS: Baseline EPSP amplitudes of all groups were stable. During treatment with propofol before high f requency stimulation (HFS),LTP amplitude was the same as that of control (P>0.05),whereas when given after HFS, propofol significantly lowered the amplitude of LTP compared with control (P<0.01). On the other hand, LTP could not be induced after treatment of propofol with APV, however, the amplitude of LTP increased transiently and decreased to baseline rapidly after treatment with propofol and CNQX (P<0.05). CONCLUSION: Propofol did not affect the induction of LTP which is dependent on NMDA receptors in the CA1 area of the rat hippocampus but propofol did inhibit the LTP maintenance, which may be attributed to blockade of AMPA receptors but not to NMDA receptors.

Key words: propofol, long-term potentiation, excitatory post-synaptic potential, receptor, rat, hippocampus