Neuromodulation of Neural Networks
Department of Biology and Center for Neuroscience
Miami University, Oxford, Ohio
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Neuroscience Discoveries in Crabs
Inhibitory Synaptic Transmission
The pioneering studies showing the existence of direct inhibitory synaptic transmission were performed on the crayfish neuromuscular junction by J. Dudel and Steven Kuffler in 1961 (Dudel & Kuffler, 1961. Presynaptic inhibition at the crayfish neuromuscular junction, J. Physiol. (Lond), 155: 543-562; also (Takeuchi & Takeuchi, 1967, J. Physiol. (Lond), 191: 575-590), and in the crayfish stretch receptor (Kuffler & Eyzaguirre, 1955, J. Gen Physiol, 130: 326-373).
Glutamate as Excitatory Transmitter
Glutamate was first discovered to be an excitatory neurotransmitter using crab muscle by Van Harreveld and Mendelson in 1959 (Van Harreveld and Mendelson, 1959. Glutamate-induced contractions in crustacean muscle. J. Cell Comp. Physiol. 54:85-94). However, glutamate is inhibitory in the crustacean central nervous system, even in response to activity from neurons that produce a glutamatergic excitatory response in muscle!
GABA as Inhibitory Transmitter
Identification of GABA as an inhibitory transmitter was discovered in the neuromuscular junction of Cancer borealis by Zack Hall, John Hildebrand and Ed Kravitz in 1974 (Chemistry of Synaptic transmission, Chiron Press, Newton, MA). See also (Otsuka, Iversen, Hall, Kravitz, 1966 Release of gamma-aminobutyric acid from inhibitory nerves of lobster. Proc Natl Acad Sci USA. 56:1110-1115).
TTX as Na+ Channel Blocker
The confirmation of the blocking effects of tetrodotoxin (TTX) on Na currents was made in lobster giant axons by Toshio Narahashi, John Moore and William Scott (Tetrodotoxin blockage of sodium conductance increase in lobster giant axons, 1964. J Gen Physiol. 47: 965-74).
Homeostatic Plasticity of Intrinsic Properties
Homeostatic plasticity of intrinsic neuronal properties was first described in lobster STG neurons, building the foundation of a huge body of work across many models (Turrigiano, LeMasson & Marder, 1995. Selective regulation of current densities underlies spontaneous changes in the activity of cultured neurons. J Neurosci, 15: 3640-3652).
Plateau Potentials
The first description of the role of plateau potentials was made by David Russell and Daniel Hartline working with lobster STG neurons clearly implicating intrinsic neuronal properties in network dynamics (Russell and Hartline, 1978. Bursting neural networks: a reexamination. Science, 200, 453-456).
Electrical Synapses
Electrical synapses were discovered by E.J. Furshpan and David Potter in 1959 working with nerve fibers of the abdominal nerve cord of the crayfish (Furshpan & Potter, 1959. Transmission at the giant motor synapses of the crayfish. J. Physiol. (Lond), 145: 289-325).
Na-K Pump
The Na-K pump was first characterized and shown to have the properties of an ATPase (with dependence on external Na+ and internal K+, etc.) by Jens Christian Skou working on a preparation of leg nerves from the shore crab Carcinus maenas in 1957. He earned the Nobel Prize for Chemistry in 1997 for this work. (Skou, 1957. The influence of some cations on an adenosine triphosphatase from peripheral nerves. Biochem. Biophys. Acta, 23: 394-401).