Neurological Effects of Marine Toxins

2017 ◽  
Author(s):  
Kazuma Nakagawa
Keyword(s):  
Action Potential ◽  
Domoic Acid ◽  
Signs And Symptoms ◽  
Na Channels ◽  
Action Potential Generation ◽  
Potential Generation ◽  
Marine Toxins ◽  
Voltage Gated ◽  
Distinct Mechanism ◽  
Neurological Effects

Human ingestion of marine toxins can produce various neurological effects, often involving the voltage-gated Na+ channels that are critical for action potential generation and propagation. Diagnosis for most marine neurotoxin is made clinically, and thus recognizing the signs and symptoms of each toxin, and obtaining the appropriate history, is essential. Major marine neurotoxins-tetrodotoxin, saxitoxin, ciguatoxin, brevetoxin, and domoic acid, have a distinct mechanism and clinical manifestation.

scholarly journals Voltage-gated sodium channels in neocortical pyramidal neurons display Cole-Moore activation kinetics

2017 ◽  
Author(s):  
Mara Almog ◽  
Tal Barkai ◽  
Angelika Lampert ◽  
Alon Korngreen
Keyword(s):  
Action Potential ◽  
Sodium Channels ◽  
Pyramidal Neurons ◽  
Brain Slices ◽  
Action Potential Generation ◽  
Potential Generation ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels ◽  
Gating Mechanism ◽  
Cortical Pyramidal Neurons

AbstractExploring the properties of action potentials is a crucial step towards a better understanding of the computational properties of single neurons and neural networks. The voltage-gated sodium channel is a key player in action potential generation. A comprehensive grasp of the gating mechanism of this channel can shed light on the biophysics of action potential generation. Most models of voltage-gated sodium channels assume it obeys a concerted Hodgkin and Huxley kinetic gating scheme. Here we performed high resolution voltage-clamp experiments from nucleated patches extracted from the soma of layer 5 (L5) cortical pyramidal neurons in rat brain slices. We show that the gating mechanism does not follow traditional Hodgkin and Huxley kinetics and that much of the channel voltage-dependence is probably due to rapid closed-closed transitions that lead to substantial onset latency reminiscent of the Cole-Moore effect observed in voltage-gated potassium conductances. This may have key implications for the role of sodium channels in synaptic integration and action potential generation.

scholarly journals Curbing action potential generation or ATP-synthase leads to a decrease in in-cell pyruvate dehydrogenase activity in rat cerebrum slices

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Benjamin Grieb ◽  
Sivaranjan Uppala ◽  
Gal Sapir ◽  
David Shaul ◽  
J. Moshe Gomori ◽  
...  
Keyword(s):  
Action Potential ◽  
Atp Synthase ◽  
Neural Activity ◽  
Pyruvate Dehydrogenase ◽  
Cerebral Metabolism ◽  
Neuronal Firing ◽  
Action Potential Generation ◽  
Potential Generation ◽  
Drastic Increase ◽  
Rat Cerebrum

AbstractDirect and real-time monitoring of cerebral metabolism exploiting the drastic increase in sensitivity of hyperpolarized 13C-labeled metabolites holds the potential to report on neural activity via in-cell metabolic indicators. Here, we followed the metabolic consequences of curbing action potential generation and ATP-synthase in rat cerebrum slices, induced by tetrodotoxin and oligomycin, respectively. The results suggest that pyruvate dehydrogenase (PDH) activity in the cerebrum is 4.4-fold higher when neuronal firing is unperturbed. The PDH activity was 7.4-fold reduced in the presence of oligomycin, and served as a pharmacological control for testing the ability to determine changes to PDH activity in viable cerebrum slices. These findings may open a path towards utilization of PDH activity, observed by magnetic resonance of hyperpolarized 13C-labeled pyruvate, as a reporter of neural activity.

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