At clinically relevant concentrations the anaesthetic/amnesic thiopental but not the anticonvulsant phenobarbital interferes with hippocampal sharp wave-ripple complexes

Papatheodoropoulos, Costas; Sotiriou, Evangelos; Kotzadimitriou, Dimitrios; Drimala, Panagiota

doi:10.1186/1471-2202-8-60

Cited by 21 publications

(14 citation statements)

References 101 publications

(180 reference statements)

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“…With 10 μM of etomidate, slice tissue concentration of ≥4 μM is expected to be reached during the application period ( Voss et al, 2016 ), which is within the range (4-12 μM) required to induce a state of deep anaesthesia in experimental animals ( De Paepe et al, 1999 ). Clinical concentrations of thiopental range between 10 and 100 μM ( Pryor et al, 2004 ; Veselis et al, 2004 ; Papatheodoropoulos et al, 2007 ). The use of 10 μM thiopental was selected because when this concentration in the brain is reached, the experimental animals lose their righting reflex ( Gustafsson et al, 1996 ) and humans fail to respond to verbal commands ( Hung et al, 1992 ).…”

Section: Discussionmentioning

confidence: 99%

The effect of general anaesthetics on brain lactate release

Hadjihambi

Karagiannis

Theparambil

et al. 2020

European Journal of Pharmacology

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The effects of anaesthetic agents on brain energy metabolism may explain their shared neurophysiological actions but remain poorly understood. The brain lactate shuttle hypothesis proposes that lactate, provided by astrocytes, is an important neuronal energy substrate. Here we tested the hypothesis that anaesthetic agents impair the brain lactate shuttle by interfering with astrocytic glycolysis. Lactate biosensors were used to record changes in lactate release by adult rat brainstem and cortical slices in response to thiopental, propofol and etomidate. Changes in cytosolic nicotinamide adenine dinucleotide reduced (NADH) and oxidized (NAD + ) ratio as a measure of glycolytic rate were recorded in cultured astrocytes. It was found that in brainstem slices thiopental, propofol and etomidate reduced lactate release by 7.4 ± 3.6% (P < 0.001), 9.7 ± 6.6% (P < 0.001) and 8.0 ± 7.8% (P = 0.04), respectively. In cortical slices, thiopental reduced lactate release by 8.2 ± 5.6% (P = 0.002) and propofol by 6.0 ± 4.5% (P = 0.009). Lactate release in cortical slices measured during the light phase (period of sleep/low activity) was ~25% lower than that measured during the dark phase (period of wakefulness) (326 ± 83 μM vs 430 ± 118 μM, n = 10; P = 0.04). Thiopental and etomidate induced proportionally similar decreases in cytosolic [NADH]:[NAD + ] ratio in astrocytes, indicative of a reduction in glycolytic rate. These data suggest that anaesthetic agents inhibit astrocytic glycolysis and reduce the level of extracellular lactate in the brain. Similar reductions in brain lactate release occur during natural state of sleep, suggesting that general anaesthesia may recapitulate some of the effects of sleep on brain energy metabolism.

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Section: Discussionmentioning

confidence: 99%

The effect of general anaesthetics on brain lactate release

Hadjihambi

Karagiannis

Theparambil

et al. 2020

European Journal of Pharmacology

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“…A Gaussian FIR band‐pass filter with corrected phase delay was applied to the LFP in two frequency bands: 2–30 and 80–250 Hz to extract the low‐frequency (LF) SW and high‐frequency (HF) ripple components, respectively. The 80 Hz lower cutoff for the ripple band was chosen to better match the room temperature recordings (Papatheodoropoulos, Sotiriou, Kotzadimitriou, & Drimala, ). For both the LF and HF filtered signals, the root mean square (RMS) was computed every 5ms in a 10ms moving window.…”

Section: Methodsmentioning

confidence: 99%

Disruption of perineuronal nets increases the frequency of sharp wave ripple events

et al. 2017

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Hippocampal sharp wave ripples (SWRs) represent irregularly occurring synchronous neuronal population events that are observed during phases of rest and slow wave sleep. SWR activity that follows learning involves sequential replay of training-associated neuronal assemblies and is critical for systems level memory consolidation. SWRs are initiated by CA2 or CA3 pyramidal cells (PCs) and require initial excitation of CA1 PCs as well as participation of parvalbumin (PV) expressing fast spiking (FS) inhibitory interneurons. These interneurons are relatively unique in that they represent the major neuronal cell type known to be surrounded by perineuronal nets (PNNs), lattice like structures composed of a hyaluronin backbone that surround the cell soma and proximal dendrites. Though the function of the PNN is not completely understood, previous studies suggest it may serve to localize glutamatergic input to synaptic contacts and thus influence the activity of ensheathed cells. Noting that FS PV interneurons impact the activity of PCs thought to initiate SWRs, and that their activity is critical to ripple expression, we examine the effects of PNN integrity on SWR activity in the hippocampus. Extracellular recordings from the stratum radiatum of horizontal murine hippocampal hemisections demonstrate SWRs that occur spontaneously in CA1.As compared with vehicle, pre-treatment (120 min) of paired hemislices with hyaluronidase, which cleaves the hyaluronin backbone of the PNN, decreases PNN integrity and increases SWR frequency. Pre-treatment with chondroitinase, which cleaves PNN side chains, also increases SWR frequency. Together, these data contribute to an emerging appreciation of extracellular matrix as a regulator of neuronal plasticity and suggest that one function of mature perineuronal nets could be to modulate the frequency of SWR events. K E Y W O R D Schondrotinase, hippocampus, hyaluronidase, protease, PV interneuron

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“…slices (thickness of 0.5 mm): first, spontaneous SPWs with amplitudes of 0.5 mV and incidences of 2-3 Hz (Yanovsky et al, 1995;Maier et al, 2002Maier et al, , 2003Papatheodoropoulos and Kostopoulos, 2002;Kubota et al, 2003;Colgin et al, 2004;Papatheodoropoulos et al, 2007); and second, afferent stimulation-induced SPWs with amplitudes of up to 5 mV and incidences of 4-10 events per minute (Behrens et al, 2005). In the following discussion, we will refer to the former as basal SPWs as their generation is independent of extra experimental manipulations.…”

Section: Comparison With Previous Studies In Conventional Hippocampalmentioning

confidence: 99%

Adenosine as an endogenous regulating factor of hippocampal sharp waves

Wong

et al. 2008

Hippocampus

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The rodent hippocampus exhibits population activities called sharp waves (SPWs) during slow wave sleep and wake immobility. SPWs are important for hippocampal-cortical communication and memory consolidation, and abnormal sharp wave-ripple complexes are closely related to epileptic seizures. Although the SPWs are known to arise from the CA3 circuit, the local mechanisms underlying their generation are not fully understood. We hypothesize that endogenous adenosine is a local regulator of hippocampal SPWs. We tested this hypothesis in thick mouse hippocampal slices that encompass a relatively large hippocampal circuit and have a high propensity of generating spontaneous in vitro SPWs. We found that application of adenosine A1 receptor antagonists induced in vitro SPWs and that such induction was sensitive to blockade by NMDA receptor antagonists. By contrast, an increase in endogenous adenosine via pharmacological inhibition of adenosine transporters or adenosine degrading enzymes suppressed spontaneous in vitro SPWs. We thus suggest that the initiation and incidence of sharp wave-like population events are under tight control by the activity of endogenously stimulated A1 receptors.

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At clinically relevant concentrations the anaesthetic/amnesic thiopental but not the anticonvulsant phenobarbital interferes with hippocampal sharp wave-ripple complexes

Cited by 21 publications

References 101 publications

The effect of general anaesthetics on brain lactate release

The effect of general anaesthetics on brain lactate release

Disruption of perineuronal nets increases the frequency of sharp wave ripple events

Adenosine as an endogenous regulating factor of hippocampal sharp waves

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