Age-dependent emergence of caffeine-assisted voltage oscillations in the endopiriform nucleus of rats

Neurosci Res. 2013 May-Jun;76(1-2):16-21. doi: 10.1016/j.neures.2013.02.010. Epub 2013 Mar 18.

Abstract

The gustatory insular cortex (IC) is connected with not only the somatosensory cortex, but also the endopiriform nucleus (EPN). We have previously revealed that low-frequency electrical stimulation to the IC can elicit membrane potential oscillations at a frequency of 8-10 Hz in the somatosensory cortex of rat brain slices under bath-application of caffeine. Using the same procedure, we investigated whether the EPN has the ability to generate oscillations, and whether such oscillations emerge age-dependently. Electrical stimulations were delivered to the IC, and field potentials were recorded from the EPN. In the case of slices made from mature rats, stable field potential oscillations at 8-10 Hz were induced in the EPN after repetitive stimulations. Optical recordings revealed that signals traveled from the IC to the EPN by way of the claustrum. Generation of oscillations was N-methyl-d-aspartate (NMDA) receptor activity-dependent, since oscillatory phases disappeared following application of NMDA receptor antagonist. In slices from immature rats, however, oscillations were not induced. IC stimulation can thus age-dependently elicit membrane potential oscillations in the EPN, and the EPN oscillations were NMDA receptor activity-dependent. These findings suggest that developmental changes in properties of the EPN might contribute to development of information integration, including gustatory information.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging
  • Animals
  • Caffeine / pharmacology*
  • Central Nervous System Stimulants / pharmacology*
  • Cerebral Cortex / drug effects*
  • Cerebral Cortex / physiology*
  • Electric Stimulation
  • Membrane Potentials / drug effects
  • Organ Culture Techniques
  • Rats
  • Rats, Wistar

Substances

  • Central Nervous System Stimulants
  • Caffeine