| 1. |
- Lindvall-Axelsson, M, et al.
(author)
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Actions of sex steroids and corticosteroids on rabbit choroid plexus as shown by changes in transport capacity and rate of cerebrospinal fluid formation
- 1990
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In: Neurological Research. - 0161-6412. ; 12:3, s. 181-186
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Journal article (peer-reviewed)abstract
- The effect of betamethasone on choroid plexus transport and CSF formation in rabbits was studied. Following 5 days of daily treatment with betamethasone the CSF production rate was reduced by 43% as measured by ventriculo-cisternal perfusion with radioactive inulin. Accordingly, the Na(+)-K(+)-ATPase activity and the transport capacity in the choroid plexus, measured in terms of choline (10(-5) M) uptake and accumulation in vitro, decreased (in the lateral ventricles by 31% in both cases). Isolated choroid plexuses from rabbits were also used to determine uptake and accumulation of choline and the activities of various types of ATPases following pretreatment of the animals with 17-beta-oestradiol, alone or in combination with progesterone. The combined treatment reduced the choline uptake by 35% and also lowered the activity of Na(+)-K(+)-ATPase by 31% without influencing tissue wet weight. Thus, the demonstrated influences of glucocorticoids and sex steroids on the transport capacity in the choroid plexus seem to be important components in their postulated effects on intracranial hypertension.
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| 2. |
- Lindvall-Axelsson, M, et al.
(author)
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Changes in transport functions of isolated rabbit choroid plexus under the influence of oestrogen and progesterone
- 1989
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In: Acta Physiologica Scandinavica. - 0001-6772. ; 136:1, s. 107-111
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Journal article (peer-reviewed)abstract
- Isolated choroid plexuses from rabbits were used to determine uptake and accumulation of 10(-5) M radiolabelled choline (expressed as tissue/medium ratio) and the activities of various types of ATPases (based on ouabain inhibition and bicarbonate stimulation) following pre-treatment of the animals with 0.5 mg kg-1 17-beta-oestradiol, alone or in combination with 2 mg kg-1 progesterone. The combined treatment reduced the choline uptake by 35% and also lowered the activity of Na+,K+-ATPase by 31%, without influencing tissue wet weight. The reduction in HCO3-ATPase was smaller and not statistically significant. There was a tendency also for oestrogen alone to lower these activities, but only by less than 20%. The Ca2+,Mg2+-ATPase activity was not significantly affected by any of the hormones.
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| 3. |
- Lindvall-Axelsson, M, et al.
(author)
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Corticosteroid action on choroid plexus: reduction in Na+-K+-ATPase activity, choline transport capacity, and rate of CSF formation
- 1989
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In: Experimental Brain Research. - 0014-4819. ; 77:3, s. 605-610
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Journal article (peer-reviewed)abstract
- Glucocorticoids have a well-known clinical effect on brain edema and intracranial hypertension, but the mechanism of action is still poorly understood. In the present report the effect of beta-methasone on choroid plexus transport and CSF formation was studied. Following 5 days of daily treatment with betamethasone the CSF production rate in rabbits was reduced by 43% as measured by ventriculo-cisternal perfusion with radioactive inulin. Accordingly, the transport capacity in the choroid plexus, measured in terms of choline uptake and accumulation in vitro, and the activity of Na+--K+-ATPase decreased in both rabbit (in the lateral ventricles by 31 and 31%, respectively) and rat (by 16 and 24%, respectively). Thus, the demonstrated influence of glucocorticoids on these functions of the choroid plexus seem to be important components in their therapeutic effect on intracranial hypertension.
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| 4. |
- Nilsson, C, et al.
(author)
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Simultaneous and continuous measurement of choroid plexus blood flow and cerebrospinal fluid production: effects of vasoactive intestinal polypeptide
- 1991
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In: Journal of Cerebral Blood Flow and Metabolism. - 1559-7016. ; 11:5, s. 861-867
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Journal article (peer-reviewed)abstract
- Using laser-Doppler flowmetry during ventriculocisternal perfusion with inulin-[14C]carboxylic acid, choroid plexus blood flow (CPBF) and CSF production were measured simultaneously in rats during periods of 3 h. Blood flow and CSF production decreased only slightly during control experiments. The effect of vasoactive intestinal polypeptide (VIP) was studied at different concentrations of the peptide given either intraventricularly or intravenously. Intraventricular administration of VIP (10(-9) or 10(-7) M) resulted in a decrease in CSF production of up to 30%, while CPBF increased by 20%, also demonstrating that CSF production and blood flow are not directly coupled in the choroid plexus. When infused intravenously, VIP (10 or 100 pmol/kg/min) increased CPBF, an effect partly antagonized at higher concentrations owing to a VIP-induced systemic hypotension. No effect of VIP on CSF production could be seen with intravenous administration.
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