In Vivo Whole-Cell Recording of Odor-Evoked Synaptic Transmission in the Rat Olfactory Bulb

J Neurosci. 2003 May 15;23(10):4108-16. doi: 10.1523/JNEUROSCI.23-10-04108.2003.

Abstract

One of the first steps in the coding of olfactory information is the transformation of synaptic input to action potential firing in mitral and tufted (M/T) cells of the mammalian olfactory bulb. However, little is known regarding the synaptic mechanisms underlying this process in vivo. In this study, we examined odor-evoked response patterns of M/T and granule cells using whole-cell recording in anesthetized, freely breathing rats. We find that odor-evoked excitatory responses in M/T cells typically consist of bursts of action potentials coupled to the approximately 2 Hz respiration rhythm. Odor-evoked, rhythmic M/T cell excitation is reliable during odor presentation (2-4 sec); in contrast, both excitatory responses of granule cells and M/T cell lateral inhibition adapt quickly after the first respiration cycle in the presence of odorants. We also find that the amplitude and initial slope of odor-evoked synaptic excitation play an important role in regulating the timing of M/T cell spikes. Furthermore, differences in odor concentration alter the shape of odor-evoked excitatory synaptic responses, the latency of M/T cell spikes, and the timing of M/T cell lateral inhibition.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Action Potentials / physiology
  • Animals
  • Animals, Newborn
  • Evoked Potentials, Somatosensory / physiology*
  • Excitatory Postsynaptic Potentials / physiology
  • Female
  • Male
  • Neurons, Afferent / cytology
  • Neurons, Afferent / physiology
  • Odorants*
  • Olfactory Bulb / cytology
  • Olfactory Bulb / physiology*
  • Patch-Clamp Techniques / methods*
  • Rats
  • Rats, Sprague-Dawley
  • Reaction Time / physiology
  • Synapses / physiology
  • Synaptic Transmission / physiology*