Spatial segregation of neuronal calcium signals encodes different forms of LTP in rat hippocampus

• Published in: The Journal of physiology 2006-01, Vol.570 (1), p.97-111
• Main Authors: Raymond, Clarke R., Redman, Stephen J.
• Format: Article
• Language: English
• Subjects: Animals; Calcium - metabolism; Calcium Channel Blockers - pharmacology; Calcium Channels - metabolism; Calcium Channels, L-Type - drug effects; Calcium Channels, L-Type - metabolism; Calcium Signaling - drug effects; Dendritic Spines - drug effects; Dendritic Spines - metabolism; Excitatory Postsynaptic Potentials - drug effects; Hippocampus - cytology; Hippocampus - drug effects; Hippocampus - metabolism; In Vitro Techniques; Inositol 1,4,5-Trisphosphate Receptors; Kinetics; Long-Term Potentiation - drug effects; Macrocyclic Compounds; Male; Neurons - drug effects; Neurons - metabolism; Neuroscience; Nifedipine - pharmacology; Oxazoles - pharmacology; Rats; Rats, Wistar; Receptors, Cytoplasmic and Nuclear - antagonists & inhibitors; Receptors, Cytoplasmic and Nuclear - metabolism; Receptors, N-Methyl-D-Aspartate - metabolism; Ruthenium Red - pharmacology; Ryanodine Receptor Calcium Release Channel - drug effects; Ryanodine Receptor Calcium Release Channel - metabolism; Synaptic Transmission - drug effects
• ISSN: 0022-3751; 1469-7793
• DOI: 10.1113/jphysiol.2005.098947

Calcium regulates numerous processes in the brain. How one signal can coordinate so many diverse actions, even within the same neurone, is the subject of intense investigation. Here we have used two-photon calcium imaging to determine the mechanism that enables calcium to selectively and appropriately induce different forms of long-term potentiation (LTP) in rat hippocampus. Short-lasting LTP (LTP 1) required activation of ryanodine receptors (RyRs), which selectively increased calcium in synaptic spines. LTP of intermediate duration (LTP 2) was dependent on activation of inositol 1,4,5-trisphosphate (IP 3 ) receptors (IP 3 Rs) and subsequent calcium release specifically in dendrites. Long-lasting LTP (LTP 3) was selectively dependent on L-type voltage-dependent calcium channels (L-VDCCs), which generated somatic calcium influx. Activation of NMDA receptors was necessary, but not sufficient, for the generation of appropriate calcium signals in spines and dendrites, and the induction of LTP 1 and LTP 2. These results suggest that the selective induction of different forms of LTP is achieved via spatial segregation of functionally distinct calcium signals.