Effects of bacterial endotoxin on regulation of the heart, a sensory-CNS-motor nerve circuit and neuromuscular junctions: Crustacean model

Saelinger, Christa M.; McNabb, Micaiah; McNair, Ruchael; Bierbower, Sonya M.; Cooper, Robin L.

doi:10.1016/j.cbpa.2019.110557

Cited by 7 publications

(9 citation statements)

References 50 publications

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“…Since the membrane potential of the muscle rapidly hyperpolarizes while the amplitude of the evoked EJPs takes longer to occur, the increased amplitude is not due to an increased driving gradient on the muscle through the ionotropic glutamate receptors. This supports a presynaptic effect since the evoked amplitude is a more synchronized occurrence of vesicle fusion and there are no changes in the amplitude of spontaneous events during LPS exposure on the crayfish opener muscle [25]. However, 5-HT (100nM) at the crayfish NMJ increased the evoked responses by an IP3 induced secondary messenger cascade to promote vesicle docking as well as increase the occurrence of spontaneous quantal events [30,33,45].…”

Section: Discussionsupporting

confidence: 56%

“…Thus, the secondary effects of cytokines make it challenging to determine the interaction of LPS and neuromodulators during synaptic transmission. The isolated NMJ of the crayfish, bathed in a known minimal physiological saline of salts, allows an assessment of LPS and 5-HT that is independent of the whole animal and the circulatory system, as high concentrations of LPS injected into the circulation can kill crayfish [25].…”

Section: Discussionmentioning

confidence: 99%

“…It was shown that LPS from Serratia marcescens increases the synaptic efficiency of the glutamatergic synapses at the crayfish neuromuscular junction (NMJ). It appears the mechanisms of action increasing the amplitude of evoked excitatory junction potentials are presynaptic, enhancing vesicle fusion [ 5 , 25 , 26 ]. 5-HT also enhances the amplitude of evoked excitatory junction potentials at the crayfish NMJ by increasing the evoked vesicle fusion [ 27 , 28 , 29 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Bacterial Endotoxin LPS on Serotonergic Modulation of Glutamatergic Synaptic Transmission

Bernard

Greenhalgh

Istas

et al. 2020

Biology

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The release of the endotoxin lipopolysaccharides (LPS) from gram-negative bacteria is key in the induction of the downstream cytokine release from cells targeting cells throughout the body. However, LPS itself has direct effects on cellular activity and can alter synaptic transmission. Animals experiencing septicemia are generally in a critical state and are often treated with various pharmacological agents. Since antidepressants related to the serotonergic system have been shown to have a positive outcome for septicemic conditions impacting the central nervous system, the actions of serotonin (5-HT) on neurons also exposed to LPS were investigated. At the model glutamatergic synapse of the crayfish neuromuscular junction (NMJ), 5-HT primarily acts through a 5-HT2A receptor subtype to enhance transmission to the motor neurons. LPS from Serratia marcescens also enhances transmission at the crayfish NMJ but by a currently unknown mechanism. LPS at 100 µg/mL had no significant effect on transmission or on altering the response to 5-HT. LPS at 500 µg/mL increased the amplitude of the evoked synaptic excitatory junction potential, and 5-HT in combination with 500 µg/mL LPS continued to promote enhanced transmission. The preparations maintained responsiveness to serotonin in the presence of low or high concentrations of LPS.

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Section: Discussionsupporting

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Effect of Bacterial Endotoxin LPS on Serotonergic Modulation of Glutamatergic Synaptic Transmission

Bernard

Greenhalgh

Istas

et al. 2020

Biology

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“…Recently, it was demonstrated that exposure to LPS from Pseudomonas aeruginosa and Serratia marcescens rapidly hyperpolarized skeletal muscle in larval Drosophila and crayfish. The rapid (immediate) and transitory (minutes) response is dependent on LPS concentration and type [22][23][24][25]. In addition, the evoked and quantal postsynaptic responses in both the crayfish and Drosophila neuromuscular junctions (NMJs) decreased in amplitude rapidly and slowly started to increase in amplitude upon removal of LPS, which indicated that LPS had blocked the postsynaptic glutamatergic receptors.…”

Section: Introductionmentioning

confidence: 99%

“…The two responses, hyperpolarization and glutamate receptor blockage, have not been reported prior to 2021 [22][23][24]. The mechanism behind the hyperpolarization had not yet been elucidated but was approached by investigating if the effect could be accounted for by Cl − flux or tetraethylammonium (TEA)-sensitive channels (i.e., voltage-gated K + or calcium-activated potassium channels).…”

Section: Introductionmentioning

confidence: 99%

Rapid and Direct Action of Lipopolysaccharide (LPS) on Skeletal Muscle of Larval Drosophila

Potter

Meade

Potter

et al. 2021

Biology

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The endotoxin lipopolysaccharide (LPS) from Gram-negative bacteria exerts a direct and rapid effect on tissues. While most attention is given to the downstream actions of the immune system in response to LPS, this study focuses on the direct actions of LPS on skeletal muscle in Drosophila melanogaster. It was noted in earlier studies that the membrane potential rapidly hyperpolarizes in a dose-dependent manner with exposure to LPS from Pseudomonas aeruginosa and Serratia marcescens. The response is transitory while exposed to LPS, and the effect does not appear to be due to calcium-activated potassium channels, activated nitric oxide synthase (NOS), or the opening of Cl− channels. The purpose of this study was to further investigate the mechanism of the hyperpolarization of the larval Drosophila muscle due to exposure of LPS using several different experimental paradigms. It appears this response is unlikely related to activation of the Na-K pump or Ca2+ influx. The unknown activation of a K+ efflux could be responsible. This will be an important factor to consider in treatments of bacterial septicemia and cellular energy demands.

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Acute lipopolysaccharide (LPS)-induced cell membrane hyperpolarization is independent of voltage gated and calcium activated potassium channels

McCubbin,

Meade,

Harrison

et al. 2024

Comparative Biochemistry and Physiology Part C: Toxicology &

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Effects of bacterial endotoxin on regulation of the heart, a sensory-CNS-motor nerve circuit and neuromuscular junctions: Crustacean model

Cited by 7 publications

References 50 publications

The Effect of Bacterial Endotoxin LPS on Serotonergic Modulation of Glutamatergic Synaptic Transmission

The Effect of Bacterial Endotoxin LPS on Serotonergic Modulation of Glutamatergic Synaptic Transmission

Rapid and Direct Action of Lipopolysaccharide (LPS) on Skeletal Muscle of Larval Drosophila

Acute lipopolysaccharide (LPS)-induced cell membrane hyperpolarization is independent of voltage gated and calcium activated potassium channels

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