A positron emission tomography study of cerebral blood flow and oxygen metabolism in healthy male volunteers anaesthetized with eltanolone

Wessén, Arne; Widman, M; Andersson, Jan; Hartvig, Per; Valind, Sven; Hetta, Jerker; Långström, Bengt

doi:10.1111/j.1399-6576.1997.tb04867.x

Cited by 7 publications

(5 citation statements)

References 29 publications

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“…29,30 However, the studies above demonstrate that with many commonly used anaesthetic agents, this coupling is lost. 25 rGMR has been found to be decreased disproportionately (to a greater extent) when compared with CBF. This leads to the concept of ‘luxury perfusion’, 26,31,32 which is a phenomenon of oxygen delivery to tissue in excess of metabolic requirement.…”

Section: Discussionmentioning

confidence: 89%

“…Although the mechanism of action of many anaesthetic agents is not fully understood, it is known that neuronal activity is depressed by GA. 24 It is extremely difficult to directly measure cerebral metabolism directly in vivo and studies have used a number of proxy measures, including changes in cerebral uptake of oxygen (CMRO 2 ) and relative glucose metabolic rate (rGMR) to identify changes in cerebral metabolic rate caused by anaesthetic agents. 25,26 Sevoflurane was found to decrease global cerebral GMR by 56% (p < 0.01). 27 Propofol induced a decrease in rGMR by 54% (p < 0.01).…”

Section: Discussionmentioning

confidence: 93%

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Purine nucleoside use as surrogate markers of cerebral ischaemia during local and general anaesthetic carotid endarterectomy

et al. 2019

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Objectives: In periods of cerebral ischaemia, adenosine triphosphate is metabolised, leading to accumulation of adenosine inosine and hypoxanthine. These can be measured in real time using peripheral blood samples intraoperatively. The primary aim of this study was to describe changes in purine concentrations in a cohort of patients undergoing carotid endarterectomy under general anaesthetic, and to evaluate correlation between changes in values with major perioperative steps. The secondary aim was to compare changes in concentrations with a previous cohort of patients who had undergone carotid endarterectomy under local anaesthetic. Methods: This was a prospective observational study. Purine concentrations were determined from arterial line samples and measured via an amperometric biosensor at specific time points during carotid endarterectomy. Mean arterial pressure was manipulated to maintain steady cerebral perfusion pressure throughout the procedure. These results were analysed against data from a cohort of patients who underwent carotid endarterectomy under local anaesthetic in previously published work. Results: Valid results were obtained for 37 patients. Purine concentrations at baseline were 3.02 ± 1.11 µM and 3.16 ± 1.85 µM for the unshunted and shunted cohorts, respectively. There was no significant change after 30 min of carotid clamping at 2.07 ± 0.89 and 2.4 ± 3.09 µM, respectively (both p > 0.05). Peak purine during the clamp phase in the loco-regional anaesthetic cohort was 6.70 ± 3.4 µM, which was significantly raised compared to both general anaesthetic cohorts (p = 0.004). There were no perioperative neurological events in either cohort. Conclusion: This small study does not demonstrate conclusive evidence that purine nucleosides can be used as a marker of cerebral ischaemia; the comparisons to the loco-regional anaesthetic data offer information about differences in the cerebral adenosine triphosphate metabolism between general anaesthetic and loco-regional anaesthetic. We hypothesise that the lack of a rise in purine nucleosides under general anaesthetic may be caused by a decrease in the cerebral metabolic rate and loss of metabolic rate-blood flow coupling caused by general anaesthetic agents.

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Section: Discussionmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 93%

Purine nucleoside use as surrogate markers of cerebral ischaemia during local and general anaesthetic carotid endarterectomy

et al. 2019

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“…The interaction may occur at several levels; the uptake of allopregnanolone to the brain from the blood might be impaired; there can be a reduction in the number of high affinity binding sites for allopregnanolone; the blood flow can be changed and influence the distribution of allopregnanolone. There exists indications of all these possibilities in the literature (Barnes, 1996; Friedman et al ., 1996; Wessen et al ., 1997; Concas et al ., 1999; Wang et al ., 2001b; Zhu et al ., 2001). However, in the most important area for the studied test, the hippocampus, there was no significant change in the allopregnanolone concentration.…”

Section: Discussionmentioning

confidence: 99%

3β‐20β‐dihydroxy‐5α‐pregnane (UC1011) antagonism of the GABA potentiation and the learning impairment induced in rats by allopregnanolone

Türkmen

Lundgren

Birzniece

et al. 2004

Eur J of Neuroscience

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Allopregnanolone is a progesterone metabolite and GABA-A receptor modulator with benzodiazepine like effects, including decreased learning and memory. In vitro 3beta-hydroxypregnane steroids antagonize allopregnanolone-induced effects, but no antagonism has been shown in vivo. Our purpose was to evaluate 3beta-20beta-dihydroxy-5alpha-pregnane (UC1011) as a blocker of allopregnanolone-induced effects in vivo and in vitro in rats. We tested adult male Wistar rats in the Morris water maze 8 min after daily injections (i.v.) of allopregnanolone 2 mg/kg (n = 21); allopregnanolone : UC1011 2 : 6 (n = 7), 2 : 8 (n = 7), 2 : 20 (n = 14) mg/kg; UC1011 20 mg/kg (n = 14); or vehicle (10% 2-hydroxypropyl-beta-cyclodextrin, n = 4). Studies of chloride ion uptake into cortical and hippocampal membrane preparations were performed. The latency to find the hidden platform was still high in the allopregnanolone-injected group on day 6. Day 3-6 rats injected with allopregnanolone and UC1011 (2 : 20 mg/kg) had lower latency (P < 0.05), compared to the allopregnanolone-injected group. The group that only received UC1011 learned the location of the platform as fast as the controls. There was no significant difference in swim speed between groups. The time spent swimming close to the pool wall was in the allopregnanolone : UC1011 group (2 : 20 mg/kg) significantly decreased (P < 0.05, day 3-6), compared to the allopregnanolone-injected group. The increased chloride ion uptake induced by increasing dosage of allopregnanolone in the presence of 10 micro m GABA was significantly decreased with UC1011 (P < 0.01), in both cortical and hippocampal homogenates. In conclusion, UC1011 can via antagonism at the GABA-A receptor reduce the negative allopregnanolone effect on learning in the water maze.

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“…FUNCTIONAL imaging modalities such as positron emission tomography or single photon emission computed tomography have revealed many details concerning the effect of common anesthetic agents (e.g., isoflurane) on cerebral blood flow and metabolism. [1][2][3][4][5][6][7][8] The effect of anesthesia on task-induced brain activation, however, is less well established. Functional magnetic resonance imaging (fMRI) offers a very promising approach to investigate this phenomenon.…”

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confidence: 99%

Subanesthetic Isoflurane Affects Task-induced Brain Activation in a Highly Specific Manner

Heinke¹,

Schwarzbauer

2001

Anesthesiology

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A positron emission tomography study of cerebral blood flow and oxygen metabolism in healthy male volunteers anaesthetized with eltanolone

Abstract: Eltanolone anaesthesia was shown to reduce cerebral oxygen metabolism and cerebral blood flow in healthy volunteers. There were no signs of ischaemic effects.

Cited by 7 publications

References 29 publications

Purine nucleoside use as surrogate markers of cerebral ischaemia during local and general anaesthetic carotid endarterectomy

Purine nucleoside use as surrogate markers of cerebral ischaemia during local and general anaesthetic carotid endarterectomy

3β‐20β‐dihydroxy‐5α‐pregnane (UC1011) antagonism of the GABA potentiation and the learning impairment induced in rats by allopregnanolone

Subanesthetic Isoflurane Affects Task-induced Brain Activation in a Highly Specific Manner

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