Old, memory-deficient rats do not show a change in the threshold for long-term potentiation (LTP) induction in hippocampal region CA1. This observation suggests that defective NMDA receptor mechanisms at the Schaffer collateral—CA1 pyramidal cell synapse cannot explain age-related LTP induction deficits that are observed under some stimulation protocols. The effects of aging on functional elect...

Previous studies have shown that the expression of the neuropeptide galanin in the hippocampus is altered by seizures and that exogenous administration of galanin into the hippocampus attenuates seizure severity. To address the role of endogenous galanin in modulation of hippocampal excitability and its possible role in seizure mechanisms, we studied two types of transgenic mice: mice with a ta...

Long-term potentiation (LTP) which has long been considered a cellular model for learning and memory is defined as a lasting enhancement in synaptic transmission efficacy. This cellular mechanism has been demonstrated reliably in the hippocampus and the amygdala-two limbic structures implicated in learning and memory. Earlier studies reported on the ability of cortical stimulation of the entorh...

A series of brief, high-frequency trains of electrical stimulation delivered to the perforant-path results in long-term potentiation (LTP) of the dentate gyrus as measured by average evoked potentials (EPs). Similar increases in dentate evoked potentials have been reported after natural learning. Previous studies of this behavioral LTP have not adequately controlled for ongoing behavior at the ...

NMDA receptor-mediated long-term potentiation (LTP) of dentate granule cell responses to perforant path stimulation was inhibited by the kappa 1 opioid receptor agonist U69,593. This inhibition was reversed stereospecifically by naloxone and blocked by the selective kappa 1 antagonist norbinaltorphimine (NBNI). NBNI, by itself, had no effect on LTP induced by threshold stimulation but significa...

Transcranial magnetic stimulation (TMS) is being proposed as a method of choice for the treatment of clinical depression, yet its action in the brain is still not well understood. In previous studies we found that TMS has a long-term effect on reactivity of the hippocampus to perforant path stimulation. Since the efficacy of antidepressants is highly age-dependent, we studied possible age-relat...

introduction: low-frequency stimulation (lfs) has a delaying effect on kindled seizures acquisition. in the present study we examined the role of galanin receptors in the inhibitory effects of lfs on kindled seizures induced by electrical stimulation of perforant path. methods: animals were stimulated daily at the ad threshold intensity with a rapid kindling procedure. lfs was applied immediate...

objective: it has been suggested that low frequency stimulation (lfs) exerts its inhibitory effect on epileptogenesis through adenosine receptors activation. in the present study, effect of different lfs frequencies on a1 and a2a receptors gene expression was investigated in perforant path kindled seizures. materials and methods: animals were kindled by perforant path stimulation. afterdischarg...

Double-pulse stimulation of the perforant path input to the dentate gyrus was used in the following experiments to produce paired pulse depression in that site. This effect provided an estimate of GABA-mediated recurrent inhibition. The depression was enhanced by drugs that facilitate or mimic GABA action and attenuated by drugs which block GABA transmission. Paired-pulse depression was signifi...