Abstract
OBJECTIVE: To directly examine the effects of carnosine on neuronal excitation and inhibition in rat hippocampus in vivo. METHODS: Artificial cerebrospinal fluid with carnosine was directly administrated over the exposed rat hippocampus. The changes of neuron activity in the CA1 region of hippocampus were evaluated by orthodromically- and antidromically-evoked potentials, as well as paired-pulse stimulation paradigm. RESULTS: In both orthodromic and antidromic response potentials, carnosine transformed population spikes (PSs) with single spike into epileptiform multiple spikes. In addition, similar to the effect of (-aminobutyric acid(A) (GABA(A)) antagonist picrotoxin, carnosine decreased paired-pulse stimulating depression significantly. However, no significant change was observed in the spontaneous field potentials during the application of carnosine. CONCLUSION: The results indicate a disinhibition-induced excitation effect of carnosine on the CA1 pyramidal neurons. It provides important information against the application of carnosine as a potential anticonvulsant in clinical treatment.