Differential effects of norepinephrine on hippocampal complex-spike and θ-neurons

Kevin Pang, Greg M. Rose

Research output: Contribution to journalArticlepeer-review

60 Scopus citations

Abstract

The central noradrenergic system has long been postulated to modulate learning and memory. A brain structure known to be important in these functions is the hippocampus. Since the hippocampus receives a noradrenergic projection from the locus coeruleus, knowledge of norepinephrine's actions in the hippocampus may help determine its role in learning and memory. In the present study, the effects of norepinephrine were examined on two hippocampal cell types: complex-spike and θ-neurons. In the hippocampus, there is good evidence that complex-spike cells are pyramidal neurons, while θ-neurons are interneurons. Extracellular action potentials from hippocampal neurons were recorded using multibarrel glass micropipettes. Drugs were locally applied using pressure micro-ejection. Norepinephrine inhibited the spontaneous firing of complex-spike cells, while θ-neurons were excited. The inhibitory response of complex-spike neurons was mediated by an α1-receptor. However, selective agonists for the α2- and β-noradrenergic receptors excited the complex-spike cells. The noradrenergic-induced excitatory response of θ-neurons was also mediated by α2 and β-receptors. This study provides evidence that locally applied norepinephrine produces different responses on two types of hippocampal neurons. Furthermore, these differential responses arise primarily from the activation of distinct populations of noradrenergic receptors.

Original languageEnglish (US)
Pages (from-to)146-158
Number of pages13
JournalBrain Research
Volume425
Issue number1
DOIs
StatePublished - Nov 3 1987
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Clinical Neurology
  • Molecular Biology
  • Neuroscience(all)
  • Developmental Biology

Keywords

  • Complex-spike cell
  • Hippocampus
  • Interneuron
  • Noradrenaline
  • Pyramidal cell
  • α-Receptor
  • β-Receptor
  • θ-Neuron

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