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Heruye SH, Warren TJ, Kostansek IV JA, Draves SB, Matthews SA, West PJ, Simeone KA, Simeone TA. Ascorbic Acid Reduces Neurotransmission, Synaptic Plasticity, and Spontaneous Hippocampal Rhythms in In Vitro Slices. Nutrients 2022; 14:nu14030613. [PMID: 35276972 PMCID: PMC8839482 DOI: 10.3390/nu14030613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 12/26/2022] Open
Abstract
Ascorbic acid (AA; a.k.a. vitamin C) is well known for its cellular protection in environments of high oxidative stress. Even though physiological concentrations of AA in the brain are significant (0.2–10 mM), surprisingly little is known concerning the role of AA in synaptic neurotransmission under normal, non-disease state conditions. Here, we examined AA effects on neurotransmission, plasticity and spontaneous network activity (i.e., sharp waves and high frequency oscillations; SPW-HFOs), at the synapse between area 3 and 1 of the hippocampal cornu ammonis region (CA3 and CA1) using an extracellular multi-electrode array in in vitro mouse hippocampal slices. We found that AA decreased evoked field potentials (fEPSPs, IC50 = 0.64 mM) without affecting V50s or paired pulse facilitation indicating normal neurotransmitter release mechanisms. AA decreased presynaptic fiber volleys but did not change fiber volley-to-fEPSP coupling, suggesting reduced fEPSPs resulted from decreased fiber volleys. Inhibitory effects were also observed in CA1 stratum pyramidale where greater fEPSPs were required for population spikes in the presence of AA suggesting an impact on the intrinsic excitability of neurons. Other forms of synaptic plasticity and correlates of memory (i.e., short- and long-term potentiation) were also significantly reduced by AA as was the incidence of spontaneous SPW-HFOs. AA decreased SPW amplitude with a similar IC50 as fEPSPs (0.65 mM). Overall, these results indicate that under normal conditions AA significantly regulates neurotransmission, plasticity, and network activity by limiting excitability. Thus, AA may participate in refinement of signal processing and memory formation, as well as protecting against pathologic excitability.
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Affiliation(s)
- Segewkal H. Heruye
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Ted J. Warren
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Joseph A. Kostansek IV
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Samantha B. Draves
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Stephanie A. Matthews
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Peter J. West
- Department of Pharmacology & Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT 84112, USA;
| | - Kristina A. Simeone
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Timothy A. Simeone
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
- Correspondence:
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