TY - JOUR
T1 - Changes in membrane potential and the intracellular calcium concentration during CSD and OGD in layer V and layer II/III mouse cortical neurons
AU - Gniel, Helen M.
AU - Martin, Rosemary L.
PY - 2010/12
Y1 - 2010/12
N2 - Cortical spreading depression (CSD) is an episode of electrical silence following intense neuronal activity that propagates across the cortex at μ3-6 mm/min and is associated with transient neuronal depolarization. CSD is benign in normally perfused brain tissue, but there is evidence suggesting that repetitive CSD contributes to infarct growth following focal ischemia. Studies to date have assumed that the cellular responses to CSD are uniform across neuronal types because there are no data to the contrary. In this study, we investigated the effect of CSD on membrane potential and the intracellular calcium concentration ([Ca2+]i) of mouse layer V and layer II/III pyramidal neurons in brain slices. To place the data in context, we made similar measurements during anoxic depolarization induced by oxygen and glucose deprivation (OGD). The [Ca2+]i was quantified using the low-affinity ratiometric indicator Fura-4F. During both CSD- and OGD-induced depolarization, the membrane potential approached 0 mV in all neurons. In layer V pyramids OGD resulted in an increase in [Ca2+]i to a maximum of 3.69 ± 0.73 (SD) μM (n = 12), significantly greater than the increase to 1.81 ± 0.70 μM in CSD (n = 34; P < 0.0001). Membrane potential and [Ca 2+]i returned to nearly basal levels following CSD but not OGD. Layer II/III neurons responded to CSD with a greater peak increase in [Ca 2+]i than layer V neurons (2.88 ± 0.6 μM; n = 9; P < 0.01). We conclude there is a laminar difference in the response of pyramidal neurons to CSD; possible explanations are discussed.
AB - Cortical spreading depression (CSD) is an episode of electrical silence following intense neuronal activity that propagates across the cortex at μ3-6 mm/min and is associated with transient neuronal depolarization. CSD is benign in normally perfused brain tissue, but there is evidence suggesting that repetitive CSD contributes to infarct growth following focal ischemia. Studies to date have assumed that the cellular responses to CSD are uniform across neuronal types because there are no data to the contrary. In this study, we investigated the effect of CSD on membrane potential and the intracellular calcium concentration ([Ca2+]i) of mouse layer V and layer II/III pyramidal neurons in brain slices. To place the data in context, we made similar measurements during anoxic depolarization induced by oxygen and glucose deprivation (OGD). The [Ca2+]i was quantified using the low-affinity ratiometric indicator Fura-4F. During both CSD- and OGD-induced depolarization, the membrane potential approached 0 mV in all neurons. In layer V pyramids OGD resulted in an increase in [Ca2+]i to a maximum of 3.69 ± 0.73 (SD) μM (n = 12), significantly greater than the increase to 1.81 ± 0.70 μM in CSD (n = 34; P < 0.0001). Membrane potential and [Ca 2+]i returned to nearly basal levels following CSD but not OGD. Layer II/III neurons responded to CSD with a greater peak increase in [Ca 2+]i than layer V neurons (2.88 ± 0.6 μM; n = 9; P < 0.01). We conclude there is a laminar difference in the response of pyramidal neurons to CSD; possible explanations are discussed.
UR - http://www.scopus.com/inward/record.url?scp=78650866778&partnerID=8YFLogxK
U2 - 10.1152/jn.00922.2009
DO - 10.1152/jn.00922.2009
M3 - Article
SN - 0022-3077
VL - 104
SP - 3203
EP - 3212
JO - Journal of Neurophysiology
JF - Journal of Neurophysiology
IS - 6
ER -