Alanna Watt, Mark van Rossum, Sacha Nelson, Gina Turrigiano

Activity Coregulates Quantal AMPA and NMDA Currents at Neocortical Synapses.
Neuron, Vol. 26, 659-670, June, 2000

AMPA and NMDA are coexpressed at many central synapses, but the factors that control the ratio of these two receptors are not well understood. We recorded mixed miniature or evoked synaptic currents arising from coactivation of AMPA and NMDAP receptors and found that the long-lasting changes in activity scaled both currents up and down proportianally through changes in the number of postsynaptic receptors. The ratio of AMPA and NMDA current was similar at different synapses onto the same neuron, and this relationship was preserved following activity-dependent synaptic scaling. These data show that AMPA and NMDA receptors are tightly corregulated by activity at synapses at which they are both expressed and suggest that a mechanism exists to actively maintain a constant receptor ratio across a neuron's synapses. We thank Steven Erat for the preparation of cultures.

Rabin BM, Joseph JA, Erat S.

Effects of exposure to different types of radiation on behaviors mediated by peripheral or central systems.
Advances in Space Research 1998;22(2):217-25. PMID: 11541399 [PubMed - indexed for MEDLINE]
The effects of exposure to ionizing radiation on behavior may result from effects on peripheral or on central systems. For behavioral endpoints that are mediated by peripheral systems (e.g., radiation-induced conditioned taste aversion or vomiting), the behavioral effects of exposure to heavy particles (56Fe, 600MeV/n) are qualitatively similar to the effects of exposure to gamma radiation (60Co) and to fission spectrum neutrons. For these endpoints, the only differences between the different types of radiation are in terms of relative behavioral effectiveness. For behavioral endpoints that are mediated by central systems (e.g., amphetamine-induced taste aversion learning), the effects of exposure to 56Fe particles are not seen following exposure to lower LET gamma rays or fission spectrum neutrons. These results indicate that the effects of exposure to heavy particles on behavioral endpoints cannot necessarily be extrapolated from studies using gamma rays, but require the use of heavy particles.