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1

The choroid plexus - cerebrospinal fluid system: undervaluated pathway of neuroendocrine signaling into the brain

100%

Skipor J. , Thiery J.-C.

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nr 3

EN

The cerebrospinal fluid (CSF) is a major part of the extracellular fluid of the central nervous system. The function of the CSF and the tissue that secretes it, the choroid plexus (CP), has traditionally been thought as providing the brain with essential nutrients, removing products of neuronal activity of the central nervous system, and providing mechanical support for the brain’s fragile cellular network. More recent studies suggest, however, that the CP and CSF system play a much more active role in the function of the central nervous system being a target, source and pathway for neuroendocrine signaling within the brain.

2

Glikoproteina P w barierze krew-mozg a wrazliwosc na iwermektyne

100%

Skipor J. , Thiery J.-C

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nr 04

384-386

3

Thyroid hormones in the cerebrospinal fluid of the third ventricle of adult female sheep during different periods of reproductive activity

80%

Skipor J. , Misztal T. , Szczepkowska A.

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nr 4

EN

Thyroid hormones (THs) are obligatory for transition from breeding season to anestrus in sheep. In this process, THs act during a very limited time of the year and primarily within the brain. In ewes chronically equipped for sampling cerebrospinal fluid (CSF) from the third ventricle, we have characterized the concentrations of total and free thyroxine (T4), triiodothyronine (T3), and total reverse T3 (rT3) in the CSF during breeding season, anestrus and during a critical period required for transition to anestrus (December-March). The total T4, T3, rT3 and free T3 average concentrations (± SEM) in CSF were 1.5 ± 0.07 ng/ml, 14.5 ± 1.2 pg/ml, 43 ± 7.4 pg/ml, and 0.6 ± 0.05 pg/ml, respectively, and all were significantly lower (p < 0.001) than in blood plasma except free T4 (12.6 ± 1.1 pg/ml), which was similar to that in plasma. There was a seasonal trend (p < 0.05) in the concentration of total T3 (highest in December) and free T4 (highest in November) in the CSF that does not follow that in blood plasma. During the period of transition to anestrus the CSF total T3/TT4 molar ratio and free T3/ T4 ratio were significantly lower (p < 0.05 and p < 0.01, respectively) than in blood plasma, while the total rT3/T4 ratio was significantly higher (p < 0.01) at the end of this period (March). Additionally, the CSF total rT3 concentrations were also significantly correlated with the CSF total T4 levels (r = 0.57; p < 0.05). In conclusion, the CSF in sheep may serve as a considerable source of thyroid hormones for neuroendocrine events. The lack of significant changes in THs concentrations in the CSF during the period of transition to anestrus indicate that neither seasonal changes of THs circulating in the blood plasma nor THs circulating in the CSF actively drive the transition to anestrus.

4

Contractile effect of PGF2alpha and PGE2 on isolated branches of uterine and ovarian artery in different days of estrous cycle and early pregnancy in pigs

80%

Skipor J. , Pikulinska M. , Stefanczyk-Krzymowska S.

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nr 4

EN

The contractile effects of PGF₂α (3 × 10⁻⁶ to 10⁻⁴ M) and PGE₂ (10⁻⁷ to 10⁻⁵ M) were examined on isolated branches of ovarian artery (OA) and extramyometrial branches of uterine artery (UA) collected from pigs in the luteal (day 10-12) and follicular phase (day 17-20) of the estrous cycle, and during early pregnancy (day 10-12). Strong contraction was demonstrated in both arteries during all investigated periods in response to PGF2α, which was significantly higher (P < 0.01) than to PGE₂, being negligible in the follicular phase. In UA, the effective dose of PGF₂α (ED50) amounted 7.9 × 10⁻⁶ M and 6.3 × 10⁻⁶ M in the luteal and follicular phase, and 5.0 × 10⁻⁶ M in early pregnancy. ED50 for PGE₂ reached 5.0 × 10⁻⁷ M in the luteal phase, and 4.1 × 10⁻⁷ M in early pregnancy. For both prostaglandins, the contraction was much stronger (P < 0.01) in OA than in UA branches. In OA, the ED50 for PGF₂α was 1.2 × 10⁻⁵ M in the luteal phase and was significantly higher (P < 0.05) than in the follicular phase (3.1 × 10⁻⁶ M) and early pregnancy (2.7 × 10⁻⁶ M). ED50 for PGE2 amounted 7.3 × 10⁻⁷ M in the luteal phase and 1.7 × 10⁻⁷ M in early pregnancy. Studies showed the influence of the estrous cycle and early pregnancy on OA branches sensitivity to the contractile effect of PGF₂α and the lack of this effect on UA branches, and the influence of the estrous cycle on UA and OA branch contraction in response to PGE2.

5

Contractile effect of PGF2α and PGE2 on isolated branches of uterine and ovarian artery in different days of estrous cycle and early pregnancy in pigs

80%

Skipor J. , Pikulińska M. , Stefańczyk-Krzymowska S.

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nr 4

6

Access of dopamine to the median eminence and brain throughout local vascular pathways in sheep

80%

Skipor J. , Wasowska B. , Picard S. , Thiery J.-C.

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nr 1

7

Luteinizing hormone and prolactin are not retrograde transferred in perihypophyseal vascular complex in ewes

80%

Skipor J. , Grzegorzewski W. , Wasowska B. , Krzymowski T.

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tom 04

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nr 2

8

Local transport of testosterone from the nasal mucosa to the carotid blood and the brain in the pig

80%

Skipor J. , Grzegorzewski W. , Krzymowski T. , Einer-Jensen N.

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2000

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tom 03

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nr 1

EN

Local counter current transfer of substances between venous and arterial vessels has been found in the perihypophyseal vascular complex after administration into the supraorbital vein. The present experiments investigate whether similar transfer could be found after nasal administration of testosterone. Experiments were conducted on the model of isolated pig's head perfused with autologous blood through one carotid artery. Tritium labelled testosterone was infused onto the nasal mucous. Radioactivity was measured in blood samples collected from the contralateral carotid artery (indicator of transfer), in the venous effluent from the jugular veins (indicator of absorption), and in tissue samples from the olfactory bulb, olfactory triangle, hypothalamus, mammillary body, cortex, pons, cerebellum, neurohypophysis, adenohypophysis, pia vessels and perihypophyseal vascular complex. The absorption was 11.4 ±4.6 per cent (mean ± SEM) and 0.4 ±0.3 per cent of the instilled testosterone was transferred during the 25 min collection period. The uptake of radioactivity was seen in many of the brain tissue samples representing the brain, pituitary, pia vessels and cavernous sinus - carotid rete complex, although a clear pattern was not seen. Nasally administered drugs may thus reach the brain in a relatively higher concentration than it reaches the rest of the body. This makes targeted treatment of the brain a distinct possibility. Additionally, the treatment will decrease the first-passage metabolism in the liver.

9

Effect of unilateral ovariectomy on counter-current transfer of prostaglandin F2alpha in the area of mesometrium vasculature in the pig

80%

Stefanczyk-Krzymowska S. , Grzegorzewski W. , Skipor J. , Krzymowski T.

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nr 1

10

Morphological changes in endothelial cells of uterine artery of cycling and ovariectomized-estradiol treated ewes

80%

Zezula-Szpyra A. , Gawronska B. , Skipor J.

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nr 4

11

Caffeine stimulates in vitro pituitary LH secretion in lipopolysaccharide-treated ewes

61%

Herman A. P. , Herman A. , Skipor J. , Krawczynska A. , Bochenek J. , Tomaszewska-Zaremba D.

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nr 1