Neuroscience_topics
Follow
Find tag "Hippocampus"
17.6K views | +2 today
Neuroscience_topics
Neuroscience: CNS disease, pain, brain research, ion channels, synaptic transmission, channelopathies, neuronal network
Your new post is loading...
Your new post is loading...
Scooped by Julien Hering, PhD
Scoop.it!

Altered Calcium Metabolism in Aging CA1 Hippocampal Pyramidal Neurons

Altered neuronal calcium homeostasis is widely hypothesized to underlie cognitive deficits in normal aging subjects, but the mechanisms that underlie this change are unknown, possibly due to a paucity of direct measurements from aging neurons. Using CCD and two-photon calcium imaging techniques on CA1 pyramidal neurons from young and aged rats, we show that calcium influx across the plasma membrane increases with aging, and that this change is countered by increased intracellular calcium buffering. The additional buffer in aging neurons balances the increased calcium influx following a small number (<3) action potentials, but is overwhelmed during sustained or theta-like activity which leads to a greater rise in intracellular calcium concentration in aging than that in young neurons. Our results demonstrate that calcium overload occurs regularly in aging CA1 pyramidal neurons under physiological conditions. This overload may be a critical factor in age-related decline in hippocampus-dependent cognitive function. - by Oh MM et al., The Journal of Neuroscience, 1 May 2013, 33(18): 7905-7911

Julien Hering, PhD's insight:

One of the pathways for age-related declined of hippocampus-dependent cogintive function is identified by the team of John Disterhoft

more...
No comment yet.
Scooped by Julien Hering, PhD
Scoop.it!

The Number and Organization of Ca2+ Channels in the Active Zone Shapes Neurotransmitter Release from Schaffer Collateral Synapses

The Number and Organization of Ca2+ Channels in the Active Zone Shapes Neurotransmitter Release from Schaffer Collateral Synapses | Neuroscience_topics | Scoop.it
[Abstract] Fast synaptic transmission requires tight colocalization of Ca2+ channels and neurotransmitter vesicles. It is generally thought that Ca2+ channels are expressed abundantly in presynaptic active zones, that vesicles within the same active zone have similar release properties, and that significant vesicle depletion only occurs at synapses with high release probability. Here we show, at excitatory CA3→CA1 synapses in mouse hippocampus, that release from individual vesicles is generally triggered by only one Ca2+ channel and that only few functional Ca2+ channels may be spread in the active zone at variable distances to neighboring neurotransmitter vesicles. Using morphologically realistic Monte Carlo simulations, we show that this arrangement leads to a widely heterogeneous distribution of release probability across the vesicles docked at the active zone, and that depletion of the vesicles closest to Ca2+ channels can account for the Ca2+ dependence of short-term plasticity at these synapses. These findings challenge the prevailing view that efficient synaptic transmission requires numerous presynaptic Ca2+ channels in the active zone, and indicate that the relative arrangement of Ca2+ channels and vesicles contributes to the heterogeneity of release probability within and across synapses and to vesicle depletion at small central synapses with low average release probability. - by Scimemi A. & Diamond J.S., The Journal of Neuroscience, 12 December 2012, 32(50): 18157-18176
more...
No comment yet.