Physiological and chemical analysis of neurotransmitter candidates at a fast excitatory synapse in the jellyfish Cyanea capillata (Cnidaria, Scyphozoa)

• Published in: Invertebrate neuroscience 2009-12, Vol.9 (3-4), p.167-173
• Main Authors: Anderson, Peter A. V, Trapido-Rosenthal, H. G
• Format: Article
• Language: English
• Subjects: Amino acid; Amino acids; Animals; beta-Alanine - analysis; beta-Alanine - metabolism; Biomedical and Life Sciences; Biomedicine; Cell Biology; Chemical analysis; Chromatography, High Pressure Liquid; Cnidaria; Excitatory Postsynaptic Potentials - physiology; Invertebrates; Molecular Medicine; Motor Neurons - metabolism; Nerve Net - metabolism; Neurobiology; Neurosciences; Neurotransmitter Agents - analysis; Neurotransmitter Agents - metabolism; Original Paper; Patch-Clamp Techniques; Physiological responses; Physiology; Scyphozoa - physiology; synapse; Synapses - physiology; Synaptic Transmission - physiology; taurine; Taurine - analysis; Taurine - metabolism; β-Alanine
• ISSN: 1354-2516; 1439-1104
• DOI: 10.1007/s10158-009-0095-9

Motor nerve net (MNN) neurons in the jellyfish Cyanea capillata communicate with one another by way of fast, bidirectional excitatory chemical synapses. As is the case with almost all identified chemical synapses in cnidarians, the identity of the neurotransmitter at these synapses is unclear. MNN neurons are large enough for stable intracellular recordings. This, together with the fact that they can be exposed, providing unlimited access to them and to their synapses, prompted a study of the action of a variety of neurotransmitter candidates, including those typically associated with fast synapses in higher animals. Only the amino acids taurine and β-alanine produced physiological responses consistent with those of the normal EPSP in these cells. Moreover, chemical analysis revealed that both taurine and β-alanine are present in the neurons and released by depolarization. These various findings strongly suggest that either or both of these amino acids, or a closely related compound is the neurotransmitter at the fast chemical synapses between MNN neurons.