Action potentials trigger two modes of neurotransmitter release, with a fast synchronous component and a temporally delayed asynchronous release. Asynchronous release contributes to information transfer at synapses, including at the hippocampal mossy fiber (MF) to CA3 pyramidal cell synapse where it controls the timing of postsynaptic CA3 pyramidal neuron firing. Here, we identified and characterized the main determinants of asynchronous release at the MF-CA3 synapse. We found that asynchronous release at MF-CA3 synapses can last on the order of seconds following repetitive MF stimulation. Elevating the stimulation frequency or the external Ca concentration increased the rate of asynchronous release, thus, arguing that presynaptic Ca dynamics is the major determinant of asynchronous release rate. Direct MF bouton Ca imaging revealed slow Ca decay kinetics of action potential (AP) burst-evoked Ca transients. Finally, we observed that asynchronous release was preferentially mediated by Ca influx through P/Q-type voltage-gated Ca channels, while the contribution of N-type VGCCs was limited. Overall, our results uncover the determinants of long-lasting asynchronous release from MF terminals and suggest that asynchronous release could influence CA3 pyramidal cell firing up to seconds following termination of granule cell bursting.
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http://dx.doi.org/10.1002/syn.22178 | DOI Listing |
Environ Toxicol Chem
January 2025
Windward Environmental LLC, Seattle, WA, USA.
Monitoring selenium (Se) concentrations in fish ovaries is an important tool for evaluating the ecological risk posed by Se in aquatic systems. Most guidance recommends sampling fish ovaries as closely as possible to when fish spawn on the premise that Se is mobilized from the liver to the ovary during vitellogenesis, and therefore, sampling ovaries during the early phases of oocyte maturation may underestimate egg Se concentrations at the time of spawning. In this study, we evaluated ovary Se data from two species with synchronous oocyte development (Ptychocheilus oregonensis and Prosopium williamsoni), one species with asynchronous oocyte development (Richardsonius balteatus), and one where the mode of development is unclear (Mylocheilus caurinus).
View Article and Find Full Text PDFJ Therm Biol
January 2025
College of Electrical Engineering and Automation, Fuzhou University, Fuzhou, 350116, China.
Magnetic nanoparticles (MNPs) used for magnetic hyperthermia can not only damage tumor cells after elevating to a specific temperature but also provide the temperature required for thermosensitive liposomes (TSL) to release doxorubicin (DOX). MNPs injected into tumor will generate heat under an alternating magnetic field, so the MNPs distribution can determine temperature distribution and further affect the DOX concentration used for tumor therapy. This study proposes an asynchronous injection strategy for this combination therapy in order to improve the DOX concentration value for drug therapy, in which the MNPs are injected into tumor after a certain lagging of TSL injection in order to increase the TSL concentration inside tumor.
View Article and Find Full Text PDFCRSLS
January 2025
Department of Surgery, King Saud University Medical City, Riyadh, Saudi Arabia. (Drs. Aljunaydil, Mattar, Almufawaz, AlOthman, and Alalem).
Nat Commun
January 2025
Department of Electrical and Electronic Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
Nat Commun
January 2025
College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
Permafrost is a potentially important source of deglacial carbon release alongside deep-sea carbon outgassing. However, limited proxies have restricted our understanding in circumarctic regions and the last deglaciation. Tibetan Plateau (TP), the Earth's largest low-latitude and alpine permafrost region, remains underexplored.
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