Sevoflurane Blocks Cholinergic Synaptic Transmission Postsynaptically but Does Not Affect Short-term Potentiation

Naruo, Hiroaki; Onizuka, Shin; Prince, David J.; Takasaki, Mayumi; Syed, Naweed I.

doi:10.1097/00000542-200505000-00010

Cited by 26 publications

(15 citation statements)

References 29 publications

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“…6A-C). These sites of clustering represent the putative synaptic sites at soma-to-soma synapses (Fiumara et al, 2005;Naruo et al, 2005). A more punctate distribution was observed for the non-phosphorylatable mutant Syn Ala36,Ala42 -GFP ( Fig.…”

Section: Phosphorylation Of Helix Synapsin B-domain Modulates Synapsimentioning

confidence: 79%

MAPK/Erk-dependent phosphorylation of synapsin mediates formation of functional synapses and short-term homosynaptic plasticity

Giachello

Fiumara

Giacomini³

et al. 2010

Journal of Cell Science

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SummaryMAPK/Erk is a protein kinase activated by neurotrophic factors involved in synapse formation and plasticity, which acts at both the nuclear and cytoplasmic level. Synapsin proteins are synaptic-vesicle-associated proteins that are well known to be MAPK/Erk substrates at phylogenetically conserved sites. However, the physiological role of MAPK/Erk-dependent synapsin phosphorylation in regulating synaptic formation and function is poorly understood. Here, we examined whether synapsin acts as a physiological effector of MAPK/Erk in synaptogenesis and plasticity. To this aim, we developed an in vitro model of soma-to-soma paired Helix B2 neurons, that establish bidirectional excitatory synapses. We found that the formation and activity-dependent short-term plasticity of these synapses is dependent on the MAPK/Erk pathway. To address the role of synapsin in this pathway, we generated non-phosphorylatable and pseudo-phosphorylated Helix synapsin mutants at the MAPK/Erk sites. Overexpression experiments revealed that both mutants interfere with presynaptic differentiation, synapsin clustering, and severely impair post-tetanic potentiation, a form of short-term homosynaptic plasticity. Our findings show that MAPK/Erk-dependent synapsin phosphorylation has a dual role both in the establishment of functional synaptic connections and their short-term plasticity, indicating that some of the multiple extranuclear functions of MAPK/Erk in neurons can be mediated by the same multifunctional presynaptic target.

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Section: Phosphorylation Of Helix Synapsin B-domain Modulates Synapsimentioning

confidence: 79%

MAPK/Erk-dependent phosphorylation of synapsin mediates formation of functional synapses and short-term homosynaptic plasticity

Giachello

Fiumara

Giacomini³

et al. 2010

Journal of Cell Science

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“…This may be related to sevoflurane dose. Naruo et al [7] reported that cholinergic post-synaptic transmission was inhibited by sevoflurane in a concentration dependent manner. Sato et al [15] found that high Mean ± SD, * = P < 0.05 compared to awake, determined by Tukey tests.…”

Section: Discussionmentioning

confidence: 99%

Sevoflurane anesthesia decreases cardiac vagal activity and heart rate variability

et al. 2007

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We evaluated cardiac vagal activity during sevoflurane anesthesia in neurosurgical patients. Heart rate variability was determined by power spectral analysis and entropy with the patient awake and during sevoflurane anesthesia. High frequency power (0.15-0.50 Hz) and heart rate entropy decreased during sevoflurane and these effects were significantly correlated (r = 0.71 +/- 0.12, P < 0.05). The results confirm that cardiac vagal activity was the primary determinant of heart rate variability, which was attenuated by sevoflurane.

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“…Cultured Lymnaea neurons retain their normal action potential types (Yar and Winlow, 1991; Winlow et al, 1991), transmitter identity (Syed et al, 1990; Spencer et al, 1995; Naruo et al, 2005), responsiveness to applied transmitters (Haydon, 1989; Syed et al, 1990) and responsiveness to applied general anesthetics (Spencer et al, 1995, 1996). Substantial research on the effect of anesthetics on neurotransmission in Lymnaea was accrued in Syed’s laboratory in Calgary.…”

Section: Actions Of Clinical Anesthetics On Gastropod Molluscsmentioning

confidence: 99%

“…In this case presynaptic transmitter release was unaffected, but postsynaptic nicotinic receptors were blocked in a dose dependent manner. However post-tetanic potentiation (PTP), a form of working memory, established in the absence of the anesthetic was not eliminated by it (Naruo et al, 2005). …”

Section: Actions Of Clinical Anesthetics On Gastropod Molluscsmentioning

confidence: 99%

Sense and Insensibility – An Appraisal of the Effects of Clinical Anesthetics on Gastropod and Cephalopod Molluscs as a Step to Improved Welfare of Cephalopods

et al. 2018

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Recent progress in animal welfare legislation stresses the need to treat cephalopod molluscs, such as Octopus vulgaris, humanely, to have regard for their wellbeing and to reduce their pain and suffering resulting from experimental procedures. Thus, appropriate measures for their sedation and analgesia are being introduced. Clinical anesthetics are renowned for their ability to produce unconsciousness in vertebrate species, but their exact mechanisms of action still elude investigators. In vertebrates it can prove difficult to specify the differences of response of particular neuron types given the multiplicity of neurons in the CNS. However, gastropod molluscs such as Aplysia, Lymnaea, or Helix, with their large uniquely identifiable nerve cells, make studies on the cellular, subcellular, network and behavioral actions of anesthetics much more feasible, particularly as identified cells may also be studied in culture, isolated from the rest of the nervous system. To date, the sorts of study outlined above have never been performed on cephalopods in the same way as on gastropods. However, criteria previously applied to gastropods and vertebrates have proved successful in developing a method for humanely anesthetizing Octopus with clinical doses of isoflurane, i.e., changes in respiratory rate, color pattern and withdrawal responses. However, in the long term, further refinements will be needed, including recordings from the CNS of intact animals in the presence of a variety of different anesthetic agents and their adjuvants. Clues as to their likely responsiveness to other appropriate anesthetic agents and muscle relaxants can be gained from background studies on gastropods such as Lymnaea, given their evolutionary history.

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Sevoflurane Blocks Cholinergic Synaptic Transmission Postsynaptically but Does Not Affect Short-term Potentiation

Abstract: This study demonstrates that sevoflurane blocks cholinergic synaptic transmission postsynaptically but does not affect short-term synaptic plasticity at the visceral dorsal 4-left pedal dorsal 1 synapse.

Cited by 26 publications

References 29 publications

MAPK/Erk-dependent phosphorylation of synapsin mediates formation of functional synapses and short-term homosynaptic plasticity

MAPK/Erk-dependent phosphorylation of synapsin mediates formation of functional synapses and short-term homosynaptic plasticity

Sevoflurane anesthesia decreases cardiac vagal activity and heart rate variability

Sense and Insensibility – An Appraisal of the Effects of Clinical Anesthetics on Gastropod and Cephalopod Molluscs as a Step to Improved Welfare of Cephalopods

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