| 1. |
- Morsing, P, et al.
(author)
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Renal interstitial pressure and tubuloglomerular feedback control in rats during infusion of atrial natriuretic peptide (ANP).
- 1992
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In: Acta Physiologica Scandinavica. - 0001-6772 .- 1365-201X. ; 146:3, s. 393-8
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Journal article (peer-reviewed)abstract
- Atrial natriuretic peptide (ANP), injected at physiological concentrations, is known to induce both natriuresis and diuresis. It has been suggested by some investigators that these changes result from an increasing glomerular filtration rate (GFR), but others have been unable to demonstrate an increased GFR. The tubuloglomerular feedback (TGF) mechanism is an important regulator of GFR, and the sensitivity of TGF is decreased during ANP administration. Furthermore, resetting of TGF is, in most instances, related to changes in renal interstitial hydrostatic and oncotic pressures. It is also known that ANP may increase capillary permeability which may change renal interstitial pressure. The present study was performed to examine renal interstitial pressures and the TGF mechanism during ANP infusion. In accordance with previous studies, TGF sensitivity was found to be decreased. The tubular flow rate which elicited half the maximal drop in stop-flow pressure (Psf) was increased from 18.5 to 25.7 nl min-1. In contrast, ANP infusion resulted in a decreased interstitial hydrostatic pressure and an increased interstitial oncotic pressure. From previous experiments, such changes in interstitial pressures would be expected to increase TGF sensitivity. The changes in interstitial pressure cannot, therefore, directly explain the resetting of the feedback mechanism. In conclusion, the present paper shows a decreased renal net interstitial pressure after intravenous administration of ANP.
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| 2. |
- Sano, Motoki, et al.
(author)
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Acute effects of alcohol on regional cerebral blood flow in man
- 1993
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In: Journal of Studies on Alcohol. - 0096-882X .- 1934-2683. ; 54:3, s. 369-376
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Journal article (peer-reviewed)abstract
- Acute effects of alcohol in a low (0.7 g/kg) and a high dose (1.5 g/kg) on regional cerebral blood flow (rCBF) were measured with 133Xe inhalation technique at resting conditions in 13 normals. Mean hemisphere CBF increased globally by 12% at the lower dose and 16% at the higher dose. A normal hyperfrontal flow pattern was seen in both alcohol conditions. There were, however, significant regional differences in response to alcohol. The largest rCBF increase was observed in prefrontal regions at the lower dose, and in temporal regions at the higher. Expressed in relative values (% of the whole brain CBF), the temporal rCBF increased linearly with increasing alcohol dosage, while the prefrontal rCBF showed a increase at the lower dose followed by a decrease at the higher dose. It is concluded that alcohol has two types of acute effects on rCBF, a global vasodilatory effect and some regional effects, most clearly seen in prefrontal and temporal regions. The prefrontal flow augmentation following acute alcohol intake may be related to a transient arousal reaction, which has been reported by others. The temporal flow increase may be related to effects of alcohol on emotions and mood.
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| 3. |
- Stenberg, Georg, 1947-, et al.
(author)
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Regional cerebral blood flow and extraversion
- 1993
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In: Personality and Individual Differences. - 0191-8869 .- 1873-3549. ; 15:5, s. 547-554
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Journal article (peer-reviewed)abstract
- Regional cerebral blood flow was examined in a group of 17 subjects (8 men, 9 women, ages 22-35) at rest and during three mental activations, inducing perceptual and spatial processing. The subjects completed two personality questionnaires, the Eysenck Personality Inventory and the Karolinska Scales of Personality. The aim of the study was to examine the relation between rCBF and the extraversion-introversion dimension. Earlier studies of rCBF at rest have found higher blood flow in the temporal lobes for introverts than for extraverts, and a negative correlation between extraversion and global cerebral blood flow among women. Both findings were confirmed in this group. The importance of related personality dimensions, such as impulsivity and anxiety, for rCBF differences between extraverts and introverts were examined, using scales from the KSP questionnaire. It was found that anxiety-proneness aspects of introversion were more important in determining high temporal blood flow than low-impulsivity aspects. Global CBF in women, as a measure of general arousal, was mainly related to the sensation-seeking aspects of extraversion. Results from the spatial processing tasks showed more right-hemispheric activation for introverts than extraverts in a mental rotation task.
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| 4. |
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| 5. |
- Wendt, Peter E., et al.
(author)
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Ethanol reduces asymmetry of visual rCBF responses
- 1994
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In: Journal of Cerebral Blood Flow and Metabolism. - 0271-678X .- 1559-7016. ; 14:6, s. 963-973
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Journal article (peer-reviewed)abstract
- Visual regional CBF (rCBF) responses were measured in 10 healthy male subjects before and after an ethanol dose of 1 g/kg body weight. This dose induces well-established cerebral vasodilatation. However, significant bilateral occipital increases were found in both conditions. Apparently, the coupling between neuronal activity and rCBF is preserved following ethanol. The occipital and posterior parietal flow increases were, however, larger on the right than the left side in the sober state. During inebriation the asymmetry disappeared, possibly representing a more undifferentiated processing of visual information. We propose that ethanol causes a reduced inhibition of the left posterior cortex and a reduction of right-hemisphere information processing.
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| 6. |
- Wendt, Peter E., et al.
(author)
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Ethanol reduces asymmetry of visual rCBF responses
- 1994
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In: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications Inc.. - 0271-678X .- 1559-7016. ; 14:6, s. 963-973
-
Journal article (peer-reviewed)abstract
- Visual regional CBF (rCBF) responses were measured in 10 healthy male subjects before and after an ethanol dose of 1 g/kg body weight. This dose induces well-established cerebral vasodilatation. However, significant bilateral occipital increases were found in both conditions. Apparently, the coupling between neuronal activity and rCBF is preserved following ethanol. The occipital and posterior parietal flow increases were, however, larger on the right than the left side in the sober state. During inebriation the asymmetry disappeared, possibly representing a more undifferentiated processing of visual information. We propose that ethanol causes a reduced inhibition of the left posterior cortex and a reduction of right-hemisphere information processing.
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