Acetylcholine Mediates a Slow Synaptic Potential in Hippocampal Pyramidal Cells

• Published in: Science (American Association for the Advancement of Science) Vol. 221; no. 4617; pp. 1299 - 1301
• Main Authors: Cole, A. E., Nicoll, R. A.
• Format: Journal Article
• Language: English
• Published: Washington, DC The American Association for the Advancement of Science 23-09-1983; American Association for the Advancement of Science
• Subjects: Acetylcholine - physiology; Animals; Atropine; Atropine - pharmacology; Biological and medical sciences; Brain; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; Cholinergic receptors; Cholinergics; Depolarization; Electric Stimulation; Fundamental and applied biological sciences. Psychology; Hippocampus - cytology; Hippocampus - physiology; In Vitro Techniques; Membrane potential; Membrane Potentials - drug effects; Nervous system; Neurochemistry; Neurons; Neurotransmitters; Physostigmine - pharmacology; Potassium; Pyramidal cells; Rats; Receptors; Receptors, Muscarinic - physiology; Synapses; Synapses - physiology; Vertebrates: nervous system and sense organs; Rat; Rodentia; Central nervous system; Electrophysiology; Brain (Vertebrata); Vertebrata; Mammalia; Neurotransmitter; Synaptic potential; Acetylcholine; Pyramidal neuron; Hippocampus; Rhinencephalon
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.6612345

The hippocampal slice preparation was used to study the role of acetylcholine as a synaptic transmitter. Bath-applied acetylcholine had three actions on pyramidal cells: (i) depolarization associated with increased input resistance, (ii) blockade of calcium-activated potassium responses, and (iii) blockade of accommodation of cell discharge. All these actions were reversed by the muscarinic antagonist atropine. Stimulation of sites in the slice known to contain cholinergic fibers mimicked all the actions. Furthermore, these evoked synaptic responses were enhanced by the cholinesterase inhibitor eserine and were blocked by atropine. These findings provide electrophysiological support for the role of acetylcholine as a synaptic transmitter in the brain and demonstrate that nonclassical synaptic responses involving the blockade of membrane conductances exist in the brain.