Long latency of evoked quantal transmitter release from somata of locus coeruleus neurons in rat pontine slices

Proc Natl Acad Sci U S A. 2007 Jan 23;104(4):1401-6. doi: 10.1073/pnas.0608897104. Epub 2007 Jan 16.


The locus coeruleus (LC) harbors a compact group of noradrenergic cell bodies projecting to virtually all parts of the central nervous system. By using combined measurements of amperometry and patch-clamp, quantal vesicle release of noradrenaline (NA) was detected as amperometric spikes, after depolarization of the LC neurons. After a pulse depolarization, the average latency of amperometric spikes was 1,870 ms, whereas the latency of glutamate-mediated excitatory postsynaptic currents was 1.6 ms. A substantial fraction of the depolarization-induced amperometric spikes originated from the somata. In contrast to glutamate-mediated excitatory postsynaptic currents, NA secretion was strongly modulated by the action potential frequency (0.5-50 Hz). Somatodendritic NA release from LC upon enhanced cell activity produced autoinhibition of firing and of NA release. We conclude that, in contrast to classic synaptic transmission, quantal NA release from LC somata is characterized by a number of distinct properties, including long latency and high sensitivity to action potential frequency.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials
  • Animals
  • Calcium / metabolism
  • Glutamic Acid / metabolism
  • In Vitro Techniques
  • Locus Coeruleus / cytology
  • Locus Coeruleus / metabolism*
  • Locus Coeruleus / physiology
  • Neurons / metabolism*
  • Neurotransmitter Agents / metabolism*
  • Patch-Clamp Techniques
  • Pons / metabolism*
  • Pons / physiology
  • Rats
  • Rats, Sprague-Dawley


  • Neurotransmitter Agents
  • Glutamic Acid
  • Calcium