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Norepinephrine, acting through beta-adrenergic receptors, is implicated in mammalian memory. In in vitro and in vivo studies, norepinephrine produces potentiation of the perforant path-dentate gyrus evoked potential; however, the duration and dynamics of norepinephrine-induced potentiation have not been explored over extended time periods. To characterize(More)
Theta and gamma oscillations are thought to provide signal sets that promote neural coding of cognitive processes. Over 40 yrs ago, Jeffrey Gray reported event-related changes in a narrow band of hippocampal theta (7.5-8.5 Hz) which appeared to involve norepinephrine (NE) release from, the noradrenergic nucleus, the locus coeruleus (LC). These event-related(More)
BACKGROUND β-adrenoceptor activation in the hippocampus is sufficient to induce heterosynaptic long-term potentiation of perforant path input to the dentate gyrus. However, in vitro and in vivo studies suggest the plasticity effects of β-adrenoceptor activation may vary depending on the level of receptor activation. METHODS The present experiments use an(More)
Despite numerous neuroendocrinological studies of seizures, the influence of estrogen and progesterone on seizures and epilepsy remains unclear. This may be due to the fact that previous studies have not systematically compared distinct endocrine conditions and included all relevant controls. The goal of the present study was to conduct such a study using(More)
The orexins (ORX-A/ORX-B) are neuroactive peptides known to have roles in feeding and sleep. Evidence of dense, excitatory projections of ORX-A neurons to the noradrenergic pontine nucleus, the locus ceruleus (LC), suggests ORX-A also participates in attention and memory. Activation of LC neurons by glutamate produces a beta-adrenergic receptor-mediated(More)
The locus ceruleus is activated by novel stimuli, and its activation promotes learning and memory. Phasic activation of locus ceruleus neurons by glutamate enhances the dentate gyrus population spike amplitude and results in long-term potentiation of synaptic responses recorded after 24 h. Cholinergic activation of locus ceruleus neurons increases(More)
High frequency (HF)-induced and norepinephrine (NE)-induced long-term potentiation have been hypothesized to utilize common mechanisms of induction and expression in the dentate gyrus. In vitro data tend to support this hypothesis, but few studies have been done in vivo. The present study records perforant path-evoked potentials simultaneously on two(More)
Active and total glycogen phosphorylase were measured histochemically in the entorhinal complex of male Sprague-Dawley rats. Rats were sacrificed from their home cage, or after 5 min in a novel holeboard. Hemispheres from each group were paired, sectioned and processed together. Glycogen phosphorylase reactivity highlighted entorhinal cortex in contrast to(More)
Glial cells provide energy substrates to neurons, in part from glycogen metabolism, which is influenced by glycogen phosphorylase (GP). To gain insight into the potential subfield and laminar-specific expression of GP, histochemistry can be used to evaluate active GP (GPa) or totalGP (GPa + GPb). Using this approach, we tested the hypothesis that changes in(More)
We generated transgenic mice in which a trans-synaptic tracer, wheat germ agglutinin (WGA), was specifically expressed in the locus coeruleus (LC) neurons under the control of the dopamine-β-hydroxylase (DBH) gene promoter. WGA protein was produced in more than 95% of the tyrosine hydroxylase (TH)-positive LC neurons sampled. Transynaptic transfer of WGA(More)