Visualizing hippocampal synaptic function by optical detection of Ca2+ entry through the N-methyl-D-aspartate channel.
Fura-2 and imaging technology were used to detect intracellular Ca2+ changes in CA1 pyramidal cells in hippocampal slices. During focal synaptic stimulation, one or more highly localized regions of Ca2+ elevation (hot spots) were detected in the dendrites. Ca2+ spread from the center of hot spots with properties consistent with diffusion. Several lines of evidence indicate that these hot spots were due to Ca2+ entry through N-methyl-D-aspartate synaptic channels. The spatial and temporal resolution of the method was sufficient to detect the response of single hot spots to single stimuli, thus providing a real-time method for monitoring local synaptic activity. Using this method, we show that synapses on the same dendrite differ in their probability of response and in their facilitation properties.
Malinow
R
R
Marine Biological Laboratory, Woods Hole, MA 02543.
Otmakhov
N
N
Blum
K I
KI
Lisman
J
J
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D003712:Dendrites / Q000502:physiology; D016257:Fura-2; D006624:Hippocampus / Q000502:physiology*; D066298:In Vitro Techniques; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D011336:Probability; D017966:Pyramidal Cells / Q000502:physiology*; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000378:metabolism*; D013569:Synapses / Q000502:physiology*; D013997:Time Factors
D015220:Calcium Channels; D016194:Receptors, N-Methyl-D-Aspartate; D015763:2-Amino-5-phosphonovalerate; D008274:Magnesium; D002118:Calcium; D016257:Fura-2