Overexpression of an Aplysia Shaker K+Channel Gene Modifies the Electrical Properties and Synaptic Efficacy of Identified Aplysia Neurons

• Published in: Proceedings of the National Academy of Sciences - PNAS 1992-02, Vol.89 (3), p.1133-1137
• Main Authors: Kaang, Bong-Kiun, Pfaffinger, Paul J., Seth G. N. Grant, Kandel, Eric R., Furukawa, Yasuo
• Format: Article
• Language: English
• Subjects: Action Potentials; Animals; Aplysia - physiology; Biochemistry; Biological and medical sciences; Electrical properties; Fundamental and applied biological sciences. Psychology; Ganglia; Gene Expression; Genetic Vectors; Genetics; Isolated neuron and nerve. Neuroglia; Membrane potential; Neurobiology; Neurons; Oocytes; Plasmids; Potassium Channels - physiology; Synapses - physiology; Synaptic Transmission; Transfection; Transmitters; Vertebrates: nervous system and sense organs
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.89.3.1133

Although potassium channels play a variety of roles in shaping the electrical properties of neurons, little is known about how these channels are constituted in neurons. To examine the assembly and physiological function of A-type K+channels in mature differentiated neurons, we have developed a highly efficient gene transfer method for Aplysia neurons that has allowed us to express about 107copies of the cloned Aplysia Shaker (Sh) K+channel (AK01a) in single identified cells. We find that expression of AK01a phenocopies one of the native transient K+currents (IAdepol), suggesting that the native channel carrying IAdepolis assembled as a homooligomer of AK01a. Overexpression of AK01a has substantial effect on the action potential, shortening its duration, enhancing its hyperpolarizing afterpotential, and depressing by more than half the amount of transmitter release by the action potential from the terminals. Thus, the AK01a channel not only contributes to the firing properties within a given neuron but also can regulate the signaling between interconnected cells.