The notion that calcium released through ryanodine receptors effects presynaptic neurotransmitter release is gaining acceptance with the observation that this calcium does indeed contribute to both action potential-evoked and spontaneous transmitter release in a variety of preparations. However, the dynamics of this calcium release and its impact on transmitter release has not yet been fully elucidated. Moreover, in contrast to vertebrate synapses, much less is known about the involvement of ryanodine receptors in the regulation of transmitter release at invertebrate synapses. In this study, we reconstructed specific synapses between individually identifiable preand postsynaptic neurons from Lymnaea to demonstrate that although ryanodine reduces the amplitude of the action potential-induced calcium transient, it does not however, alter the resting calcium level. These data suggest that action potential-induced calcium release through ryanodine receptors is fast and highly dynamic and in turn regulates transmitter release at reconstructed synapses between Lymnaea neurons. This study thus provides direct evidence that a dynamic ryanodine receptor-mediated calcium transient occurs with the presynaptic action potential.
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Trends Neurosci
January 2025
Hefei National Laboratory for Physical Sciences at the Microscale, Department of Neurology in the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China; Anhui Province Key Laboratory of Biomedical Imaging and Intelligent Processing, Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei 230088, China. Electronic address:
The precise organization of the complex set of synaptic proteins at the nanometer scale is crucial for synaptic transmission. At the heart of this nanoscale architecture lies the nanocolumn. This aligns presynaptic neurotransmitter release with a high local density of postsynaptic receptor channels, thereby optimizing synaptic strength.
View Article and Find Full Text PDFMol Psychiatry
January 2025
The Center of Psychosomatic Medicine, Sichuan Provincial Center for Mental Health, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.
While the highly evolutionarily conserved hypothalamic neuropeptide, oxytocin (OT) can influence cognitive, emotional and social functions, and may have therapeutic potential in disorders with social dysfunction, it is still unclear how it acts. Here, we review the most established findings in both animal model and human studies regarding stimuli which evoke OT release, its primary functional effects and the mechanisms whereby exogenous administration influences brain and behavior. We also review progress on whether OT administration can improve social symptoms in autism spectrum disorder and schizophrenia and consider possible impediments to translational success.
View Article and Find Full Text PDFBiophys J
January 2025
National Institute of Neurological Disorders and Stroke, 35 Convent Dr., Bldg. 35, Bethesda, Maryland 20892, USA. Electronic address:
Dense-core vesicles (DCVs) are found in various types of cells, such as neurons, pancreatic β-cells, and chromaffin cells. These vesicles release transmitters, peptides, and hormones to regulate diverse functions, such as the stress response, immune response, behavior, and blood glucose levels. In traditional electron microscopy after chemical fixation, it is often reported that the dense cores occupy a portion of the vesicle towards the center and are surrounded by a clear halo.
View Article and Find Full Text PDFJ Physiol
January 2025
Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark.
Synaptic vesicle (SV) trafficking toward the plasma membrane (PM) and subsequent SV maturation are essential for neurotransmitter release. These processes, including SV docking and priming, are co-ordinated by various proteins, such as SNAREs, Munc13 and synaptotagmin (Syt), which connect (tether) the SV to the PM. Here, we investigated how tethers of varying lengths mediate SV docking using a simplified mathematical model.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA 94720.
Norepinephrine in vertebrates and its invertebrate analog, octopamine, regulate the activity of neural circuits. We find that, when hungry, larvae switch activity in type II octopaminergic motor neurons (MNs) to high-frequency bursts, which coincide with locomotion-driving bursts in type I glutamatergic MNs that converge on the same muscles. Optical quantal analysis across hundreds of synapses simultaneously reveals that octopamine potentiates glutamate release by tonic type Ib MNs, but not phasic type Is MNs, and occurs via the G-coupled octopamine receptor (OAMB).
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