PubMed Health⌕ Search

Biomedical subjects

K Skolasińska

Publications and source records attributed to K Skolasińska.

At least 19 recordsLinked to original sources
PubMed1986

Effect of ammonia intoxication on cerebral blood flow, its autoregulation and responsiveness to carbon dioxide and papaverine.

Cerebral blood flow (CBF) was measured in anaesthetised cats with 133Xe clearance method under normal conditions and with hyperammonaemia. Elevation of blood ammonia concentration by an intravenous infusion of ammonium acetate caused an increase in CBF and a parallel decrease in cerebrovascular resistance (CVR). These parameters reached, however, plateau at an arterial blood ammonia level exceeding 500 mumol/l. Cerebrovascular reactivity to CO2 diminished following elevation of blood ammonia concentration and at arterial blood ammonia level exceeding 500 mumol/l it was virtually abolished. In contrast, hyperammonaemia influenced neither cerebrovascular responsiveness to papaverine nor autoregulatory properties of the cerebral circulation. It is concluded, therefore, that hyperammonaemia exerts some dilatatory effect on cerebral vessels and severely impairs chemical regulation of CBF but does not elicit cerebral vasomotor paralysis.

Ammonia↗
PubMed1986

Chemical regulation of the cerebral blood flow in cats with rostro- or prepontine transection of the brainstem.

Cerebral blood flow (CBF) and its response to hypercapnia were evaluated in cats with brainstem transected either at rostropontine (pretrigeminal preparation) or prepontine (cerveau isole preparation) level. Additionally, the effect of pentobarbital on CBF response to hypercapnia and to papaverine were examined. CBF was measured with 133 Xe intracarotid injection method. Cortical EEG activity was recorded. In rostropontine cats cerebral vessels responded with a dilatation to hypercapnia. In prepontine cats CBF response to CO2, was absent, where-as that to papaverine maintained. In rostropontine cats administration of pentobarbital, even in very low doses, caused disappearance of CBF response to hypercapnia, leaving that to papaverine. Our results support the idea that a neurogenic mechanism is involved in chemical regulation of CBF. The rostra1 part of the pontine reticular formation may be responsible for this neurogenic control.

Animals↗
PubMed1985

The effect of stimulation of the reticulo-hypothalamic-hippocampal systems on the cerebral blood flow and neocortical and hippocampal electrical activity in cats.

The effect of stimulation of the medial and lateral reticulo-hypothalamic-hippocampal (RHH) systems on cerebral blood flow (CBF) and electrical activity of the hippocampus and neocortex was examined in 19 encéphale isolé cats. ECoG was recorded from posterior sigmoid gyri and marginal gyri and hippocampal activity from dorsal hippocampus. Changes in hippocampal activity were evoked by electrical stimulation of RHH systems. CBF was measured by external monitoring of the clearance of 133Xe given as a single bolus in the carotid artery. Stimulation of the lateral system resulted in desynchronisation of ECoG and hippocampal activity without changes in CBF. Stimulation of the medial system elicited desynchronisation in ECoG modulated by theta-like synchrony, theta activity in the hippocampus and a 45% CBF increase. After atropine administration, low frequency, high voltage waves appeared in both ECoG and hippocampal activity, but no change in CBF was observed. During stimulation of the medial system there were no changes in the type of electrical activity but the CBF response was still preserved (increase by 50%). Stimulation of the lateral system did not change either the type of electrical activity or the CBF. The results indicate that the two systems of neuronal pathways, which mediate two different patterns of electrical response in the dorsal hippocampus but similar ECoG activity in the neocortex, elicit different CBF responses. It is argued that the alterations of electrical activity of the neocortex and hippocampus mediated by these two pathways depend on the cholinergic system, whereas the CBF changes depend on a different mechanism.

Action Potentials↗
PubMed1981

Cerebral blood flow and ultrastructural studies of the brain capillaries in the early state of hypertension in SHR+.

The 133Xe single bolus injection technique was used for measuring the cerebral blood flow (CBF) in spontaneously hypertensive (SHR) and normotensive rats. Their age was from 5 to 25 weeks and corresponded to the time before the initiation of the arterial blood pressure (BP) increase to the constant phase of hypertension. CBF in SHR 5 and 10 weeks of age was significantly higher than in all other groups being 155 +/- 7.2 and 151 +/- 9.3 ml/min/100 g, respectively. At 15 weeks of age the localization of the reactive products of ATP and CTP became scanty and spread over the endothelial cytoplasm. Further, at 25 weeks an enlarged number of empty pinocytic vesicles and astrocytic foot processes filled with flocculent electron dense material was found. These data suggest that the initial high CBF preceding the increase of BP can initiate the irreversible disorder of endothelial cells in brain capillaries.

Animals↗
PubMed1979

Impairment of cerebral blood flow autoregulation after hypertonic urea administration.

The effect of unilateral intracarotid administration of 3 M urea on resting cerebral blood flow, arterial blood pressure, perfusion pressure-cerebral blood flow relation, ECoG and Evans blue permeability was tested in dogs. The injection of urea was without effect on ECoG and enhanced the arterial blood pressure temporarily. Cerebral blood flow measured 10 min after the urea injection was not affected. Extravasation of Evans blue was observed in the urea-perfused hemisphere for about 40 min following the urea administration. Cerebral perfusion pressure-blood flow relation for the urea affected hemisphere studied at the time when blood-brain barrier to protein was restored revealed loss of the normal autoregulatory response, despite that it was preserved in the control hemisphere.

Animals↗
PubMed1979

Regional cerebral blood flow and visual attention in the awake isolated cerebrium of the pretrigeminal cat.

The effect of visual stimulation on cerebral blood flow (CBF) was studied in five cats with brainstem transection at the pretrigeminal level. The CBF was measured in the occipital and frontal cortex by external monitoring of the clearance of 133Xe. As a visual stimulus, a feather duster moving for 2 min in front of the cat’s eyes was used. This stimulus evoked an increase of CBF. In the occipital cortex the CBF increase was greater and comparable to that evoked by elevation of the arterial pCO2. Both in the occipital and frontal cortex the CBF response was positively correlated with the intensity of the ocular-following reflex and the cortical EEG arousal. It is concluded that the CBF increase was correlated with the degree of attention paid by the cat to the visual stimulus.

Animals↗
PubMed1978

Cerebrovascular response to intracarotid infusion of 5-hydroxytryptophan and L-DOPA in cats.

Intracarotid administration of 5-hydroxytryptophan (10 mg/kg) results in a slight vasoconstriction of cerebral vessels. L-DOPA (20 mg/kg) administered by the same route enhances cerebral blood flow. The effect on cerebral blood flow of L-DOPA (20 mg/kg) following intracarotid 5-hydroxytryptophan (10 mg/kg) administration shows a potentiation of cerebral blood flow response in non-pretreated as well as in nialamide- and reserpine-pretreated cats.

5-Hydroxytryptophan↗
PubMed1977

A blood flow increase to a visual stimulus in the occipital lobe of the cat with brainstem transection at the pretrigeminal level.

The effects of visual stimulation on the cerebral blood flow were studied in pretrigeminal cats. The visual stimulus was a feather duster which was moved for 4-5 min in front of the cats eyes. The cerebral blood flow was measured each 15 min with [133]Xe clearance method in the left occipital lobe. The visual stimulation evoked an increase of the cerebral blood flow which was accompanied by an ocular following movements and a cortical EEG desynchronization. The arterial blood pressure was unchanged. All these responses habituated rapidly when the stimulus was repeated at 15 min intervals. A similar increase of the cerebral blood flow was obtained by 9 percent CO2 inhalation. The administration of amphetamine increased the cerebral blood flow, whereas Nembutal decreased it. The visual stimulus evokes an increase of the cerebral blood flow in a condition when the lower brainstem is separated from the cerebrum.

Amphetamine↗