Muscarinic potentiation of IK in hippocampal neurons: electrophysiological characterization of the signal transduction pathway.
Central cholinergic (muscarinic) systems play an important role in learning and memory. In mammalian central neurons, muscarinic stimulation depresses several voltage-activated K+ currents and modulates synaptic transmission. Using whole-cell voltage-clamp recordings in hippocampal CA1 neurons of rat brain slices, we report that activation of muscarinic receptors potentiates a voltage-activated, sustained K+ current (IK-type). This potentiation of IK is mediated by activation of protein kinase C and involves a G-protein-linked, intracellular Ca(2+)-dependent process. This underlying second messenger pathway may prove to be important in the mediation of other previously reported muscarinic neuronal actions.
Zhang
L
L
Playfair Neuroscience Unit, Toronto Hospital Research Institute, Ontario, Canada.
Weiner
J L
JL
Carlen
P L
PL
D000818:Animals; D002118:Calcium / Q000502:physiology; D004594:Electrophysiology; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000502:physiology; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D007425:Intracellular Membranes / Q000378:metabolism; D009116:Muscarine / Q000378:metabolism*; D009474:Neurons / Q000502:physiology*; D010766:Phosphorylation; D011188:Potassium / Q000502:physiology; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction
D009116:Muscarine; D011493:Protein Kinase C; D019204:GTP-Binding Proteins; D011188:Potassium; D002118:Calcium