Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Asphyxia can cause neurologic damage in the fetus, but there are few data relating severity or duration of asphyxia to the degree of cerebral damage. We report cerebral histologic and electrophysiologic changes after asphyxia in chronically instrumented late-gestation fetal sheep. We reduced uterine blood flow to produce an ascending aortic blood oxygen content less than 1.5 mM for either 30 or 60 min (n = 13). In a subsequent protocol (n = 6), if full occlusion of the common uterine artery for 15 min did not reduce the EEG voltage to less than 20% of baseline, supplementary maternal hypoxia was added for a maximum of 120 min. Histologic outcome was assessed 3 d postinsult. Uterine artery occlusion resulted in severe hypoxemia, hypercarbia, acidosis, and an initial hypertension and bradycardia. Eight of 14 surviving fetuses showed neuronal damage, with greatest loss in the parasagittal cortex, striatum, and the CA1/2 region of the hippocampus. Neuronal damage was strongly associated with the percentage of decrease in blood pressure during the insult (r = 0.75, p less than 0.005) but not with the degree of hypoxia. No other factor was independently predictive, but, when considered separately, pH (r = 0.54; p less than 0.05) and loss of intensity of the EEG (r = 0.61, p less than 0.02) at the end of asphyxia were also correlated with outcome. The pH fell to less than 7.0 in six of eight fetuses with damage, whereas it remained greater than 7.0 in five of six without damage (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Cerebral histologic and electrocorticographic changes after asphyxia in fetal sheep. 160 25

The receptor autoradiographic distribution of opioid peptide receptors in spontaneously hypertensive rats (SHR) was compared to that of Sprague-Dawley (SD) rats, using the highly selective mu and delta opioid receptor ligands, [3H]DAGO (Tyr-D-Ala-Gly-NMe-Phe-Gly-ol) and [3H]DPDPE ([D-Pen2,D-Pen5]enkephalin), respectively. Although the distribution of these binding sites was similar in both strains, SHR showed significantly higher binding densities of mu receptors in 16 of 27 areas examined. These included the patch and matrix components of the caudate-putamen (CPu), olfactory tubercle, endopiriform nucleus, anterior cingulate cortex, ventral tegmental area lateroposteral thalamic nucleus and the ventral part of the dentate gyrus. In contrast, SHR had lower [3H]DAGO binding sites in the CA1 of the hippocampus. Conversely, SHR showed higher binding densities of delta receptors in 7 of 20 areas examined, including the CPu, CA2 and CA3 areas of the hippocampus and the central grey. High-to-low lateromedial gradients of striatal delta receptors were observed in both strains. Because opioid peptides are known to participate in locomotive behavior in rodents and in the control of blood pressure, the present results support a role of opioid peptidergic systems in the manifestation of hyperactivity and hypertension observed in SHR.
 ...
PMID:Receptor autoradiography of mu and delta opioid peptide receptors in spontaneously hypertensive rats. 166 45

Brief bilateral carotid artery ligation in adult spontaneously hypertensive rats (SHR) induced locomotor hyperactivity and lesions of the CA1 region of the hippocampus but had no effect in Wistar normotensive rats. This result suggests that high blood pressure amplifies the consequences of cerebral ischaemia. Treatment for 7 weeks with the calcium entry-blocker isradipine (5 mg/kg per day, subcutaneously) normalized blood pressure and attenuated the behavioural and histological consequences of cerebral ischaemia. Chronic treatment with hydralazine (25 mg/kg per day, subcutaneously) also normalized blood pressure but afforded no protection against the consequences of cerebral ischaemia. This suggests that the protective effect of antihypertensive treatment depends not only on the blood pressure-lowering action but may also be linked to the mechanism of action of the drug used.
 ...
PMID:Protective effects of antihypertensive treatment with isradipine on the consequences of cerebral ischaemia in the spontaneously hypertensive rat. 184 26

Global cerebral ischemia (four vessel model) was induced in renovascular hypertensive rats (two kidney, one clip model) chronically treated with intraperitoneal administration of angiotensin I converting enzyme inhibitors, either captopril (100 mg/kg per day) or Wy-44,655 (10 mg/kg per day). Mortality following cerebral ischemia was higher in renovascular hypertensive rats than in normotensive controls. Reduction of blood pressure with captopril or Wy-44,655, lowered mortality. In surviving renovascular hypertensive and normotensive rats cerebral ischemia induced hyperactivity and lesions of the CA1 area of the hippocampus. Prolonged treatment with captopril--but not with Wy-44,655--reduced hyperactivity and the extent of the CA1 lesions. In conclusion, hypertension increases mortality following cerebral ischemia but does not affect the extent of brain injury in survivors. Prior treatment with converting enzyme inhibitors lowers mortality. Treatment with captopril attenuates brain injury in survivors.
 ...
PMID:The angiotensin I converting enzyme inhibitors, captopril and Wy-44,655 attenuate the consequences of cerebral ischemia in renovascular hypertensive rats. 220 71

We investigated the putative role of nitric oxide in the expression of neuronal injury following both transient severe forebrain ischemia (CA1 neuronal injury) and transient or permanent middle cerebral artery occlusion (neocortical pannecrosis). Using the four-vessel occlusion model and increasing doses of N-omega-nitro-L-arginine, 2-40 mg/kg, we were unable to demonstrate any reduction in the percentage of CA1 cells injured following 10 min of transient severe forebrain ischemia followed by seven days of reperfusion. Higher doses proved toxic insofar as they increased the mortality following the ischemic insult. Saline-treated animals (n = 8) had 77 +/- 10% CA1 injury while those treated with 2 mg/kg of nitro-arginine i.v. had 80 +/- 7% (n = 7), and those with 10 mg/kg i.v. had 78 +/- 11% (n = 8). Two of five rats given 20 mg/kg i.v., three of eight given 40 mg/kg i.v., and two of six given 10 mg/kg i.v. followed by 3 x 10 mg/kg i.p., died. Of those treated with high-dose nitro-arginine and which survived ischemia and seven days' reperfusion, no significant reduction in CA1 injury was detected. Wistar rats and spontaneously hypertensive rats treated with either saline or nitro-arginine i.v. were exposed to 2 h of transient middle cerebral artery occlusion followed by 22 h of reperfusion. There were seven animals in each group. Wistars treated with saline had 198 +/- 67 mm3 (mean +/- S.D.) of neocortical infarction, and those treated with 10 m/kg of nitro-arginine i.v. had 199 +/- 93 mm3. Spontaneously hypertensive rats, transiently ischemic, treated with saline had 164 +/- 25 mm3 of infarct volume, while those treated with 2 mg/kg i.v. had 151 +/- 53 mm3, and those treated with 10 mg/kg i.v. had 145 +/- 29 mm3. Animals treated with 40 mg/kg i.v. had a nonsignificantly larger mean infarct volume (191 +/- 81 mm3). High dose nitro-arginine caused an increase in hypertension in the spontaneously hypertensive rats and increased the severity of focal ischemia as measured by intra-ischemic regional cerebral blood flows. A final group of seven spontaneously hypertensive rats underwent permanent middle cerebral artery occlusion and repeated dosing with N-omega-nitro-L-arginine i.p. In these animals an infarct volume of 234 +/- 60 mm3 was observed, which was again not statistically different from saline-treated controls (208 +/- 43 mm3, n = 7).(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Failure to prevent selective CA1 neuronal death and reduce cortical infarction following cerebral ischemia with inhibition of nitric oxide synthase. 752 64

Human epidemiological data show a strong association between low birth weight and hypertension in adulthood, an effect that has been ascribed to 'fetal programming'. In rats fetoplacental exposure to maternally administered dexamethasone throughout gestation reduces birth weight and produces hypertensive adult offspring, though the mechanism is unclear. Pre- and postnatal stress programmes hypothalamic-pituitary-adrenal (HPA) axis responses throughout the lifespan, an effect thought to be mediated via permanent effects on glucocorticoid receptor (GR) and/or mineralocorticoid receptor (MR) gene expression in the hippocampus. Corticosteroids also have specific central effects on blood pressure control mediated by GR and MR. This study investigated corticosterone (CORT) responses to restraint stress and GR and MR gene expression in areas of the brain postulated to mediate the central effects of corticosteroids on (i) HPA axis suppression (hippocampus), and (ii) blood pressure (organ vasculosum of the lamina terminalis (OVLT), sub-commissural organ, area postrema and nucleus tractus solitarius). Pregnant Wistar rats received dexamethasone (100 micrograms/kg.day-1) or vehicle on days 15-20 of gestation. This reduced birth weight by 11%. When the offspring were 16 weeks old, blood pressure was recorded directly and plasma CORT measured basally (AM) and after 30 min restraint. GR and MR mRNA expression were determined by in situ hybridization. Blood pressure was significantly elevated in the adult offspring of dexamethasone-treated pregnancies (dexamethasone 144 +/- 2/125 +/- 2 mm Hg vs. control 133 +/- 2.7/112 +/- 2.8 mm Hg; both p < 0.01). Offspring of dexamethasone-treated pregnancies had increased basal plasma CORT (155 +/- 29 nmol/l) compared to offspring of controls (79 +/-15 nmol/l, p < 0.05), but the CORT response to stress was similar. Hippocampal neuronal GR mRNA expression was significantly lower in the offspring of dexamethasone-treated pregnancies (dentate gyrus 20% lower, CA1 15% lower; p < 0.01). Similarly, hippocampal MR gene expression was decreased in CA1 and CA2 by 24 and 25%, respectively (p < 0.05). No differences in GR or MR mRNA expression were found in the OVLT, subcommissural organ, area postrema or nucleus tractus solitarius. These findings suggest that glucocorticoid excess in the last trimester of rat pregnancy (i) is sufficient to programme offspring hypertension; (ii) also increases basal plasma CORT levels, and (iii) permanently attenuates GR and MR mRNA expression in specific hippocampal subfields. Thus, if translated into protein, may reduce sensitivity to glucocorticoid feedback and thus contribute to the CORT excess. However, hypertension in this model is unlikely to be mediated by similar changes in GR or MR gene expression in the examined areas of the brain putatively involved in the more direct central regulation of blood pressure.
 ...
PMID:Dexamethasone in the last week of pregnancy attenuates hippocampal glucocorticoid receptor gene expression and elevates blood pressure in the adult offspring in the rat. 899 73

To elucidate the effects of aging accompanied with hypertension on brain nucleic acid, we measured both the DNA and RNA contents of six specific brain regions in adult (5-6 months old) and aged (18-22 months old) female spontaneously hypertensive rats (SHRs). Although no statistical difference was observed in the RNA content, the DNA content did tend to increase in the hippocampal CA1 of aged SHR (4.24 +/- 0.55 ng/microgram protein, mean +/- SD, n = 6) in comparison to that of adult SHR (3.21 +/- 0.71 ng/microgram protein, n = 4). Hence, aged SHRs showed a significant decrease in the RNA to DNA ratio in the CA1 subfield of the hippocampus (3.79 +/- 0.61) compared to adult SHR (5.27 +/- 0.81). On the other hand, no other regions, except for the dorsolateral region of the striatum, showed any difference in the RNA/DNA ratio between aged and adult SHR. We therefore conclude that subtle changes in the nucleic acid occur in vulnerable regions of the brain in aged SHRs.
 ...
PMID:Age-related changes in the DNA and RNA content of the brain in spontaneously hypertensive rats. 905 58

We report a 76-year-old man who developed blurred vision and dementia. He was apparently well until April 4, 1990 (70-year-old at that time) when he had a sudden onset of bilateral loss of vision. Corrected vision was 0.1 (right) and 0.09 (left). He was admitted to the ophthalmology service of our hospital on April 9, 1990, and neurological consultation was asked on April 11. Neurologic examination revealed alert and oriented man without dementia. Higher cerebral functions were intact. He had bilateral large visual field defects with loss of vision; he was only able to count the digit number with his right eye and to recognize hand movement with his left eye. Otherwise neurologic examination was unremarkable. General physical examination was also unremarkable; he had no hypertension. Cranial CT scan was normal on April 11; lumber spinal fluid contained 1 cell/microliter, 63 mg/dl of sugar, and 97 mg/dl of protein; myelin basic protein was detected, however, oligoclonal bands were absent. He was treated with methylprednisolone pulse therapy and oral steroid, however, no improvement was noted in his vision. He started to show gaze paresis to left, ideomotor apraxia, agnosia of the body, and dementia. Cranial CT scan on June 11 revealed a low density area in the deep left parietal white matter facing the trigonal area of the lateral ventricle. He was discharged on July 2, 1990. Hasegawa dementia scale was 2/32.5 upon discharge. In the subsequent course, he showed improvement in his mental capacity and Hasegawa dementia scale was 22.5/32.5 in 1991, however, no improvement was noted in his vision. In 1994, he started to show mental decline in that he became disoriented, and showed delusional ideation of self persecution and depersonalization with occasional confusional state. He also showed unsteady gait. Cranial MRI on February 13, 1996 revealed a T2-high signal intensity lesion on each side of the parietal deep white matter more on the left and another T2-high signal intensity lesion in the left pons as well as in the right thalamus. He complained of right hypochondrial pain and was admitted to another hospital on April 22, 1996. He was markedly confused and demented. He continued to show bilateral loss of vision, but no motor palsy was noted. Cranial CT scan on April 23, 1996 revealed diffuse cortical atrophy and ventricular dilatation in addition to the low density areas in both parietal deep white matter. He developed jaundice in the middle of May. Abdominal CT scan revealed multiple low-to iso-density areas in the liver and marked iso-to high-density swelling of the right kidney. The patient expired on June 9th, 1996. The patient was discussed in a neurological CPC and the chief discussant arrived at the conclusion that the patient had had a carcinomatous limbic encephalitis with optic neuropathy and a choleduct carcinoma. Other opinions entertained included acute disseminated encephalomyelitis with optic neuritis, and granulomatous angiitis of the central nervous system. Some participants thought the primary site of the carcinoma was the right kidney with metastasis to the liver. Post mortem examination revealed a mixed type carcinoma in the right kidney with liver metastases. Neuropathologic examination revealed an incomplete softening in the optic chiasm and the left optic nerve, and in the left parieto-occipital areas. (The right hemisphere was frozen for future biochemical assay.) One of the adjacent cortical arteries had an organized thrombus. Other arteries and arterioles also showed sclerotic changes. Some of the leptomeningeal arteries were positive for Congored staining as well as for beta-amyloid immunostaining. Many senile plaques were seen diffusely in the cerebral cortex and neurofibrillary tangles were seen in the CA1 area and the parahippocampal gylus. No cellular infiltrations or demyelinated foci were seen. The neuropathologic features were consistent with circulatory disturbance based on the amyloid angiopa
 ...
PMID:[A 76-year-old man with loss of vision and dementia]. 928 74

The Dahl salt-sensitive (DS) rat, a genetic model of salt-induced hypertension in humans, is more likely to develop severe vascular injuries than a rat with spontaneous hypertension. We designed an experiment to scrutinize the effects of renin-angiotensin inhibition on cognitive dysfunction in the aged, normotensive DS with a passive avoidance test. Eighteen months of treatment with a very low dose of the angiotensin-converting enzyme (ACE) inhibitor cilazapril (2.5 microg/mL in drinking water) or the angiotensin II type 1 receptor antagonist E4177 did not reduce blood pressure throughout the experiment, although in the low dose cilazapril group (12.5 microg/mL in drinking water), blood pressure dropped within 6 months after treatment began. The cilazapril treatments dose-dependently improved memory function in the aged, normotensive DS fed a low-salt diet compared with the untreated, control rats. This improvement was associated with significant increases in hippocampal CA1 cells and capillary densities in the CA1 regions compared with those in the untreated DS. Similarly, E4177 slightly improved the memory dysfunction observed in the aged DS. The cells in the hippocampal CA1 region were restored slightly, but the capillary densities were not influenced by the receptor antagonist. On the other hand, the ACE inhibitor and receptor antagonist both attenuated urinary protein excretions with an improvement of glomerular sclerosis. These data suggest that long-term treatment with an ACE inhibitor improves memory dysfunction probably through restoration of capillary and hippocampal cells. The effects are due to the inhibition of the angiotensin II type 1 receptor and probably to the enhancement of the kallikrein-kinin system.
Hypertension 1999 Sep
PMID:Long-term inhibition of renin-angiotensin system sustains memory function in aged Dahl rats. 1048

In this article we studied in vitro and in vivo the effect of calcium channel blockers (verapamil and amlodipine) on erythrocyte carbonic anhydrase I activity, on carbonic anhydrase I isolated from vascular smooth muscles, and on arterial blood pressure values in human beings and in animals. Our in vitro and in vivo results have shown that verapamil and amlodipine are strong inhibitors of carbonic anhydrase I both in erythrocytes (in human beings) and in vascular smooth muscles (in animals). In human beings calcium channel blockers reduce arterial blood pressure in subjects with hypertension and progressively reduce erythrocyte carbonic anhydrase I activity. We assume that verapamil and amlodipine possess a dual mechanism of action: the first mechanism consists of their action on calcium channels, and the second mechanism, proposed by us, shows that verapamil and amlodipine inhibit vascular smooth muscle carbonic anhydrase I activity with consecutive pH increase. The increase of pH might be an additional factor involved in intracellular calcium influx through calcium channels. This dual mechanism of action would bring new data regarding the hypotensive effect of verapamil and amlodipine, effects that might also be parallel and dependent on carbonic anhydrase I inhibition.
 ...
PMID:Hypotensive effect of calcium channel blockers is parallel with carbonic anhydrase I inhibition. 1106 85


1 2 3 4 5 6 Next >>