PO2-profiles in hippocampal slices of the guinea pig

Bingmann, D.; Kolde, G.

doi:10.1007/bf00239575

Cited by 70 publications

(44 citation statements)

References 25 publications

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“…ATP critically regulates the ability of kinases to phosphorylate substrates, and is required for protein synthesis, both of which are important for commonly studied slice phenomena such as long-term potentiation (LTP) [19]. ATP also has signalling properties in its own right through at least seven ionotropic (P2X 1−7 ) and eight G protein-coupled receptors (GPCRs; P2Y 1,2,4,6,11,12,13,14 ), and indirectly through its metabolism to ADP (P2Y 1,12,13 agonist) and adenosine, which has pronounced actions on the CNS through its four GPCRs (A 1 , A 2A , A 2B , A 3 ) [20]. Moreover, the ratio of ATP:AMP critically regulates the activity of AMP-activated protein kinase (AMPK), an enzyme that is known to regulate a number of ion channels and which is increasingly being implicated in a host of CNS functions [21,22].…”

Section: Atp: More Than Just Currencymentioning

confidence: 99%

The Purine Salvage Pathway and the Restoration of Cerebral ATP: Implications for Brain Slice Physiology and Brain Injury

Frenguelli

2017

Neurochem Res

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Brain slices have been the workhorse for many neuroscience labs since the pioneering work of Henry McIlwain in the 1950s. Their utility is undisputed and their acceptance as appropriate models for the central nervous system is widespread, if not universal. However, the skeleton in the closet is that ATP levels in brain slices are lower than those found in vivo, which may have important implications for cellular physiology and plasticity. Far from this being a disadvantage, the ATP-impoverished slice can serve as a useful and experimentally-tractable surrogate for the injured brain, which experiences similar depletion of cellular ATP. We have shown that the restoration of cellular ATP in brain slices to in vivo values is possible with a simple combination of d-ribose and adenine (RibAde), two substrates for ATP synthesis. Restoration of ATP in slices to physiological levels has implications for synaptic transmission and plasticity, whilst in the injured brain in vivo RibAde shows encouraging positive results. Given that ribose, adenine, and a third compound, allopurinol, are all separately in use in man, their combined application after acute brain injury, in accelerating ATP synthesis and increasing the reservoir of the neuroprotective metabolite, adenosine, may help reduce the morbidity associated with stroke and traumatic brain injury.

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Section: Atp: More Than Just Currencymentioning

confidence: 99%

The Purine Salvage Pathway and the Restoration of Cerebral ATP: Implications for Brain Slice Physiology and Brain Injury

Frenguelli

2017

Neurochem Res

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“…2C of Jiang, Agulian & Haddad, 1991). Anoxic regions have also been described in 600 ,um thick brainstem as well as cortical slices of adult rats (Bingmann & Kolde, 1982;Fujii, Baumgiirtl & Lubbers, 1982;Jiang et al 1991). Several factors could explain a better oxygen supply of the isolated neonatal brainstem used in the present study.…”

Section: Tissue Po2 Gradientsmentioning

confidence: 51%

Microenvironment of respiratory neurons in the in vitro brainstem‐spinal cord of neonatal rats.

Brockhaus

Ballanyi

Smith

et al. 1993

The Journal of Physiology

127

128

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SUMMARY1. O2-,K+-and pH-sensitive microelectrodes were used to measure extracellular oxygen pressure (Po2), K' activity (aK.) and pH (pH.) in ventral regions of the medulla oblongata containing respiratory neurons in the in vitro brainstem-spinal cord preparation from 0 to 4-day-old rats.2. The location of respiratory neurons was mapped by extracellular recordings with conventional microelectrodes, or with the reference barrel of ion-sensitive microelectrodes. The major populations of respiratory neurons were distributed in the ventrolateral reticular formation near the nucleus ambiguus at depths of 300-600 ,um. In this area, aK. baseline increased from 3-2 to 3-8 mm whereas steadystate values of Po2 and pHo fell from 120 to 7 mmHg and from 6-9 to 6-7, respectively.3. During rhythmic inspiratory discharges recorded with suction electrodes from ventral roots of spinal (C3-C5) and cranial (IX, X, XII) nerves, aKo transiently increased by up to 100 /M, and Po2 fell maximally by 0 4 mmHg. During episodes of non-rhythmic neuronal discharge, aKo increased by as much as 0-4 mm and Po2 decreased by about 10 mmHg. In contrast, no variations in pHo could be detected during such activities.4. Activation of medullary neurons by tetanic electrical stimulation of axonal tracts in the ventrolateral column of the spinal cord at the level of the phrenic motoneuron pool produced aKo elevations of up to 5 mm, decreases of Po2 by up to 50 mmHg, and pHo increases by a maximum of 0 07 pH units. These aKo and Po2 transients were reduced by more than 80 % during blockade of synaptic transmission with 5 mm manganese (Mn2+) and completely blocked by 1 ,tm tetrodotoxin (TTX).5. The tissue Po2 gradient as well as activity-related decreases of P2 were completely abolished after block of oxidative cellular metabolism by addition of 2-10 mm cyanide (CN-) to the bathing solution.6. Inhibition of the Na+-K+ pump by addition of 3-50 /M ouabain (3-10 min)caused a reversible increase of aKo by 0-8-3 mm, a delayed recovery of stimulusinduced aKo elevations, and produced a disturbance of the respiratory rhythm.7. The sensitivity of the respiratory network to oxygen depletion was tested by superfusing the neuraxis with hypoxic solutions gassed with N2 instead of 02(5-20 min). The response of the respiratory network to such hypoxic exposure MS 9830 J. BROCKHA US AND OTHERS consisted of an initial increase in frequency of respiratory motor output, followed by a depression of respiratory activity that terminated in a reversible loss of the respiratory rhythm.8 10. It is concluded that the oxygen supply of the ventral respiratory network is sufficient to maintain aerobic neuronal metabolism and metabolically driven Na+-K+ pump activity which allows respiratory rhythmogenesis and network function in the in vitro neonatal rat brainstem-spinal cord preparation.

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“…In the first series of experiments, we recorded mossy fiber fEPSPs in slices placed in an interface chamber that optimizes oxygen supply to the tissue (Tsacopoulos et al, 1981;Bingmann and Kolde, 1982). In response to paired-pulse stimulation in the stratum lucidum with an interstimulus interval of 40 ms, fEPSPs showed strong paired-pulse facilitation (212 Ϯ 12%; n ϭ 5) ( Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Metabolic stress, such as hypoxia, can lead to an enormous elevation of the extracellular adenosine level, which nearly completely depresses synaptic transmission in hippocampal slices (Dale et al, 2000;Frenguelli et al, 2003). When compared with interface chambers, submerged recording chambers are less optimal for oxygenation of the tissue because of a limited transfer rate of oxygen through the perfusate (Tsacopoulos et al, 1981;Bingmann and Kolde, 1982). For this reason, elevated levels of ambient adenosine are more likely to occur in submerged slices.…”

Section: Discussionmentioning

confidence: 99%

The Role of Extracellular Adenosine in Regulating Mossy Fiber Synaptic Plasticity

Kukley¹,

Schwan²,

Fredholm³

et al. 2005

J. Neurosci.

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PO2-profiles in hippocampal slices of the guinea pig

Cited by 70 publications

References 25 publications

The Purine Salvage Pathway and the Restoration of Cerebral ATP: Implications for Brain Slice Physiology and Brain Injury

The Purine Salvage Pathway and the Restoration of Cerebral ATP: Implications for Brain Slice Physiology and Brain Injury

Microenvironment of respiratory neurons in the in vitro brainstem‐spinal cord of neonatal rats.

The Role of Extracellular Adenosine in Regulating Mossy Fiber Synaptic Plasticity

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