1. A comparative descriptive analysis of systemic (sodium pentobarbital, sodium thiopentone, ketamine) and volatile (halothane, isoflurane, enflurane) general anesthetics revealed important differences in the neuronal responses of identified motor neurons and interneurons in the isolated central nervous system (CNS) and cultured identified neurons in single cell culture of Lymnaea stagnalis (L.). 2. At high enough concentrations all anesthetics eventually caused cessation of spontaneous or evoked action potentials, but volatile anesthetics were much faster acting. Halothane at low concentrations caused excitation, thought to be equivalent to the early excitatory phase of anesthesia. Strong synaptic inputs were not always abolished by pentobarbital. 3. There were cell specific concentration-dependent responses to halothane and pentobarbital in terms of membrane potential, action potential characteristics, the after hyperpolarization and patterned activity. Individual neurons generated specific responses to the applied anesthetics. 4. The inhalation anesthetics, enflurane, and isoflurane, showed little concentration dependence of effect, in contrast to results obtained with halothane. Enflurane was faster acting than halothane and isoflurane was particularly different, producing quiescence in all cells types studied at all concentrations studied. 5. Halothane, enflurane, the barbiturate general anesthetics, pentobarbital, and sodium thiopentone and the dissociative anesthetic ketamine, produced two distinctly different effects which could be correlated with cell type and their location in the isolated brain: either a decline in spontaneous and evoked activity prior to quiescence in interneurons or paroxysmal depolarizing shifts (PDS) in motor neurons, again prior to quiescence, which were reversed when the anesthetic was eliminated from the bath. In the strongly electrically coupled motor neurons, VD1 and RPD2, both types of response were observed, depending on the anesthetic used. Thus, with the exception isoflurane, all the motor neurons subjected to the anesthetic agents studied here were capable of generating PDS , but the interneurons did not do so. 6. The effects of halothane on isolated cultured neurons indicates that PDS can be generated by single identified neurons in the absence of synaptic inputs. Further, many instances of PDS in neurons that do not generate it have been found in cultured neurons. The nature of PDS is discussed.
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http://dx.doi.org/10.3389/fphys.2019.00583 | DOI Listing |
Cureus
November 2024
Integrative Medicine, Division of Yoga, Ministry of Ayush, Central Research Institute of Yoga and Naturopathy (CRIYN), Nagamangala, IND.
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November 2024
Internal Medicine/Rheumatology, Ibn Sina University for Medical and Pharmaceutical Sciences, Baghdad, IRQ.
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative motor neuron disease that leads to a gradual loss of motor neurons manifesting as progressive weakness, dysarthria, and respiratory decline, with a relatively short life expectancy. Rheumatoid arthritis (RA) is an autoimmune disorder characterized by polyarthritis and affects multiple systems. Motor neuron involvement is rare in rheumatoid arthritis.
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December 2024
Department of Human Genetics, National Institute of Pediatrics, Mexico City, Mexico.
Neuronal ceroid lipofuscinosis type 2 (CLN2) results from biallelic pathogenic variants in the gene, leading to deficient activity of the lysosomal enzyme tripeptidyl peptidase 1. We report an autopsy case of CLN2 characterized at molecular level. The patient exhibited a spectrum of neurologic symptoms including epilepsy, behavioral alterations, cognitive regression, motor impairment, and visual loss.
View Article and Find Full Text PDFNeurobiol Dis
December 2024
Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada. Electronic address:
Background: Altered balance between striatal direct and indirect pathways contributes to early motor, cognitive and psychiatric symptoms in Huntington disease (HD). While degeneration of striatal D2-type dopamine receptor (D2)-expressing indirect pathway medium spiny neurons (iMSNs) occurs prior to that of D1-type dopamine receptor (D1)-expressing direct pathway neurons, altered corticostriatal synaptic function precedes degeneration. D2-mediated signaling on iMSNs reduces their excitability and promotes endocannabinoid (eCB) synthesis, suppressing glutamate release from cortical afferents.
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December 2024
Laboratory of Stem Cell Biology and Epigenetics, School of Basic Medical Sciences, Shanghai University of Medicine & Health Sciences, 279 Zhouzhu Highway, Pudong New Area, Shanghai, 201318, China.
Midbrain dopamine (mDA) neurons participate in a wide range of brain functions through an intricate regulation of DA biosynthesis. The epigenetic factors and mechanisms in this process are not well understood. Here we report that histone demethylase JMJD3 is a critical regulator for DA biosynthesis in adult mouse mDA neurons.
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