Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the gerbil cerebral infarction was produced by unilateral carotid ligation. 3.5 hours later, when the neurological deficit was fully developed, hemisphere dopamine (DA) showed little change from normal. It seems unlikely that changes in DA are the direct cause of the turning behavior shown by these animals. Slight changes in norepinephrine (NE) occurred on the operated side but 4 hydroxy-3-methoxy phenyl-ethyleneglycol sulphate (MOPEG-SO4) levels were not affected. Significant falls in 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) were found on the operated side but there was also a trend for both 5HT and 5-HIAA to fall on the unoperated side. These changes occurred in clincally affected and unaffected animals and their clinical significance is unproven.
Stroke
PMID:Effect of experimental ischemia on neurotransmitter amines in the gerbil brain. 3 64

The effect of ischemia on catecholamine and 5-hydroxytryptamine (5-HT) levels in brain cortex was examined in the gerbil stroke model. Unilateral common carotid artery occlusion produced bilateral decrease in cortical dopamine levels in gerbils both symptomatic and asymptomatic of cerbral ischemia. The 5-HT progressively decreased only in the occluded hemisphere of ischemic animals. In p-chlorophenylalanine (PCPA)-treated gerbisl, dopamine decreased only in the occluded hemisphere of symptomatic animals, but norepinephrine became decreased bilaterally compared with controls. The 5-HT decrease was twice that seen in untreated animals. It is suggested that these results indicate initial release together with reduced synthesis of monoamines in ischemic brain. The incidence of ischemia induced by carotid occlusion decreased from 44% to 26% in PCPA-treated animals, which also suggests that depletion of 5-HT available for neuronal release prior to the induction of ischemia may reduce stroke incidence by limiting impairment of collateral vasocapacitance. PCPA pretreatment did not influence the development of edema in the occluded hemisphere of ischemic animals once ischemia was established.
Stroke
PMID:Cathecholamine and 5-hydroxytryptamine levels in ischemic brain. Influence of p-chlorophenylalanine. 14 Apr 80

Cerebral blood flow was measured in 17 baboons before and during infusion of 5-hydroxytryptamine (5-HT) into the internal carotid artery. The mean values for total cerebral blood flow, grey matter flow, and white matter flow before 5-HT infusion were 40.8, 59.2, and 12.7 ml/min/100 gm of tissue, respectively. There was no significant alteration in total blood flow or flow through grey matter when 5-HT was infused at dosages ranging from 0.5 to 10.0 microng/kg/min. A small but significant decrease in white matter blood flow was recorded when 5-HT was infused at a rate exceeding 2.5 microng/kg/min. The study indicates that in vivo, with the xenon clearance method, intra-arterial infusion of 5-HT does not significantly alter cerebral blood flow.
Stroke
PMID:Cerebrovascular response to infused 5-hydroxytryptamine in the baboon. Part 1. 5-Hydroxytryptamine infusion. 40 32

The effect of intracarotid infusion of 5-hydroxytryptamine (5-HT) on cerebral blood flow was studied in five female baboons 7 days after intramuscular injection of slow release estrogen and progesterone. The control values for total cerebral blood flow, grey matter flow, and white matter flow were 38.9, 57.5, and 11.0 ml/min/100 gm of tissue respectively. There was a statistically significant decrease in total, grey and white matter blood flow during infusion of 5-HT at dosages ranging from 0.5 to 10.0 microng/kg/min. The study indicates that in female baboons pretreated with estrogen and progesterone, intracarotid infusion of 5-HT produces a dose dependent decrease in cerebral blood flow, which did not occur in control animals.
Stroke
PMID:Cerebrovascular response to infused 5-hydroxytryptamine in the baboon. Part 2. 5 Hydroxytryptamine infusion in estrogen and progesterone treated animals. 40 33

Brain edema was induced in rats by injecting 50 mu microspheres, labelled with 85Sr, into the internal carotid artery. The use of radioactive microspheres as embolic agents enabled the number of microspheres to be determined in each cerebral hemisphere. Edema was assessed 12 or 24 h after embolization by measuring brain water content and, in some experiments, sodium and potassium. Pretreatments with dexamethasone, parachlorophenylalanine (an inhibitor of 5-hydroxytryptamine synthesis), mepyramine and metiamide (H1 and H2 histamine receptor antagonists) or aminophylline did not influence significantly the development of brain edema evaluated 24 h after embolization. Aminophylline treatment (100 mg/kg) markedly increased mortality following embolization. Gamma-butyrolactone (300 mg/kg, every 2 h) inhibited significantly the development of brain edema evaluated 12 hours after embolization. Increases in water and sodium in the embolized cerebral hemisphere were reduced by about 50%. This protective effect may be related to the known depressant action on brain metabolism.
Stroke
PMID:Influence of various agents on the development of brain edema in the rat following microembolism. Protective effect of gamma-butyrolactone. 52 4

Seizure activity as a component of the ischemic process possibly responsible for monoamine changes described in the gerbil stroke model was the subject of this study. Abnormal motor activity suggestive of seizures developed one to three hours after unilateral ligation of the common carotid artery in approximately 50% of gerbils that exhibited signs of stroke. Reduction of cortical levels of dopamine and norepinephrine was observed only when seizures occurred in association with stroke. The levels of 5-hydroxytryptamine were reduced bilaterally in animals with and without signs of stroke and were reduced further in animals with stroke plus seizures. Further study is needed to establish whether the catecholamine changes associated with ischemia-induced seizures are primary and causative or secondary to seizure activity itself. In the ischemic brain, 5-hydroxytryptamine metabolism appears disordered independent of seizure activity. Seizure activity must be taken into account when the mechanisms of disordered monoamine metabolism are being examined in the gerbil stroke model.
 ...
PMID:Ischemia-induced seizures and cortical monoamine levels. 65 65

The contractile effects of thromboxane A2 (TxA2), a labile arachidonic acid metabolite, were studied in arterial smooth muscle strips. TxA2 was generated upon the addition of 255 nM prostaglandin cyclic endoperoxide H2 to human platelet particles in the muscle bath. Using the isometric contaction produced by 40 mM K+ in isotonic saline as the reference contraction, bovine middle cerebral artery strips contracted to 153 +/- 14% of the reference response while bovine coronary and porcine coronary, renal and common carotid strips contracted to 47 +/- 3, 26 +/- 5, 43 +/- 2 and 2 +/- 1% of reference, respectively. The cerebral artery response to the TxA2 generating system was as great as the maximum response to prostaglandin F2alpha and two times the maximum response to 5-hydroxytryptamine. Because TxA2 is formed by brain tissue and released from aggregating platelets, it may be important in the pathogenesis of spasm associated with injured brain tissue or pathologic changes leading to platelet aggregation.
Stroke
PMID:Cerebral arterial smooth muscle contraction by thromboxane A2. 89 44

The effects of gamma-hydroxybutyrate (GHB) on 1) monoamine metabolism, and 2) protein synthesis were examined in a gerbil stroke model. The monoamine metabolism was studied by occluding bilateral common carotid arteries for 15 minutes followed by GHB administered intravenously 3 hours later. Tissue monoamine concentration was examined up to 8 hours after recirculation. Three hours after GHB administration, dopamine (DA) had increased to almost twice that of the non-treated group, whereas homovanillic acid, a metabolite of DA, did not show any significant difference. These results may mean that GHB will facilitate DA synthesis but that it has no influence on its release. Therefore, a DA-mediated increase in cerebral blood flow in the cerebral cortex cannot be expected. Tryptophan, a precursor of 5-hydroxytryptamine (5HT), started to increase just after recirculation reaching a level of over four times that of the control value at 2 to 3 hours, and then starting to decrease in the non-treated group. This decline in tryptophan was markedly facilitated by GHB administration within 1 hour. On the other hand, 5HT administration within 1 hour. On the other hand, 5HT increased only very slightly in the cerebral cortex 1 hour after GHB administration, the change ratio being 1/30 of tryptophan. It can therefore be speculated, that the decrease in tryptophan brought about by GHB administration is due to the improvement in disturbed protein synthesis rather than to stimulation of 5HT synthesis. Protein synthesis was studied by administering GHB 2 minutes prior to a 5-minute temporal common carotid artery occlusion. Ninety minutes after recirculation animals were given a single dose of 14C-leucine and further 60 minutes were allowed to pass before sacrifice. Autoradiographs of the GHB-treated group were compared with those of the non-treated group. With GHB pretreatment, autoradiographs showed an increased uptake of 14C-leucine in at least the hippocampus, thalamus, and hypothalamus, and in two out of three animals, there was diffusely increased uptake. Thus, it is speculated that GHB is effective in improving the protein synthesis in the postischemic period. The favorable function of GHB during cerebral ischemia is regarded by many to be prevention of energy failure by reducing cerebral metabolism. On the other hand, the results derived from the present study suggest that GHB may improve protein synthesis in the postischemic period. Thus, we suggest that GHB is useful if given at the acute stage of cerebral ischemia such as during internal carotid artery or middle cerebral artery occlusion.
 ...
PMID:[Effects of gamma-hydroxybutyrate on monoamine metabolism and protein synthesis after transient global cerebral ischemia]. 140 58

Progress in general symptomatic therapy such as avoidance of complications through nursing care, rehabilitation, and secondary prevention of stroke yield a better quality of life to stroke patients. Unfortunately, no specific drug therapy for acute stroke has been proven to be of benefit in controlled trials. However, new drugs and drug therapies such as thrombolytic therapy, 5-hydroxytryptamine agonists, NMDA receptor antagonists, and free radical scavengers are being studied.
 ...
PMID:Medical treatment of acute ischemic stroke. 172 34

We developed a constant-flow perfusion system to measure vascular responses to vasoactive agents applied intraluminally or extraluminally. The intraluminal and extraluminal sides of a cylindrical section of rabbit basilar artery were isolated completely. By loading with 0.75 g of tension, the resting condition of each preparation was made constant. The intraluminal side was perfused at a constant flow of 8 ml/min and under an intraluminal pressure of 8 mm Hg. When 30 mM KCl was administered intraluminally the preparation showed marked contraction, whereas only slight contraction was observed with extraluminal administration. When 2 x 10(-7) M 5-hydroxytryptamine was administered, no significant differences in contraction could be detected between the intraluminal and extraluminal routes. Application of 10(-6) to 10(-4) M acetylcholine after precontraction with 30 mM KCl resulted in much stronger dilatation upon intraluminal application. Thus, it was demonstrated that under certain conditions significant differences exist in the responses of rabbit basilar arteries to vasoactive agents applied intraluminally or extraluminally. This system can detect the effects of vasoactive agents administered intraluminally and extraluminally at a high level of sensitivity and shows good reproducibility as a means of analyzing vascular functions and characteristics.
Stroke 1991 Mar
PMID:Development of a new perfusion system for pharmacological study on rabbit basilar arteries. 200 8


1 2 3 4 5 6 7 Next >>