Journal
JOURNAL OF NEUROSCIENCE
Volume 29, Issue 37, Pages 11441-11450Publisher
SOC NEUROSCIENCE
DOI: 10.1523/JNEUROSCI.2387-09.2009
Keywords
-
Categories
Funding
- National Institute of Health [NS40056, MH074989]
Ask authors/readers for more resources
NMDA receptor ( NMDAR)-dependent strengthening of neurotransmitter release has been widely observed, including in layer 5 (L5) pyramidal cells of the visual cortex, and is attributed to the axonal expression of NMDARs. However, we failed to detect NMDAR-mediated depolarizations or Ca2+ entry in L5 pyramidal cell axons when focally stimulated with NMDAR agonists. This suggests that NMDARs are excluded from the axon. In contrast, local GABA(A) receptor activation alters axonal excitability, indicating that exclusion of ligand-gated ion channels from the axon is not absolute. Because NMDARs are restricted to the dendrite, NMDARs must signal to the axon by an indirect mechanism to alter release. Although subthreshold somatic depolarizations were found to spread electrotonically hundreds of micrometers through the axon, the resulting axonal potential was insufficient to open voltage-sensitive Ca2+ channels. Therefore, if NMDAR-mediated facilitation of release is cell autonomous, it may depend on voltage signaling but apparently is independent of changes in basal Ca2+. Alternatively, this facilitation may be even less direct, requiring a cascade of events that are merely triggered by NMDAR activation.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available