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2 Janelia Publications
Showing 1-2 of 2 resultsInput comparison is thought to occur in many neuronal circuits, including the hippocampus, where functionally important interactions between the Schaffer collateral and perforant pathways have been hypothesized. We investigated this idea using multisite, whole-cell recordings and Ca2+ imaging and found that properly timed, repetitive stimulation of both pathways results in the generation of large plateau potentials in distal dendrites of CA1 pyramidal neurons. These dendritic plateau potentials produce widespread Ca2+ influx, large after-depolarizations, burst firing output, and long-term potentiation of perforant path synapses. Plateau duration is directly related to the strength and temporal overlap of pathway activation and involves back-propagating action potentials and both NMDA receptors and voltage-gated Ca2+ channels. Thus, the occurrence of highly correlated SC and PP input to CA1 is signaled by a dramatic change in output mode and an increase in input efficacy, all induced by a large plateau potential in the distal dendrites of CA1 pyramidal neurons.
Many insect developmental color changes are known to be regulated by both ecdysone and juvenile hormone. Yet the molecular mechanisms underlying this regulation have not been well understood. This review highlights the hormonal mechanisms involved in the regulation of two key enzymes [dopa decarboxylase (DDC) and phenoloxidase] necessary for insect cuticular melanization, and the molecular action of 20-hydroxyecdysone on various transcription factors leading to DDC expression at the end of a larval molt in Manduca sexta. In addition, the ecdysone cascade found in M. sexta is compared with that of other organisms.