A STUDY OF ANGIOTENSIN II RECEPTORS AFTER CHRONIC INHIBITION OF NITRIC OXIDE SYNTHASE IN THE SPONTANEOUSLY HYPERTENSIVE RAT

1. Nitric oxide (NO) synthase inhibition, induces a sustained increase in blood pressure and amplifies the pressor response to infused angiotensin II (AngII). This study was designed to investigate the contribution of AngII receptors to the elevated blood pressure and enhanced pressor response to AngII in the spontaneously hypertensive rat (SHR) chronically treated with N^G-nitro-l -arginine-methyl ester (l -NAME). 2. Two groups of 13 week old female SHR were housed four to a box. Group I rats received l -NAME for 7 days (2.5 mg/kg per day) in their drinking water. Group II rats received water only. Blood pressure was monitored daily by tail-cuff plethysmography. Plasma AngII was measured by radioimmunoassay. Aortic and uterine receptor binding was determined by saturation analysis using [¹²⁵I]-Sar⁸, Ile¹)AngII. Data was analysed using the computer program ligand. 3. Mean systolic blood pressure was significantly elevated in rats treated with l -NAME compared with the control group. Plasma AngII concentration was slightly decreased in rats treated with l -NAME compared with control. Densities of both aortic and uterine AngII receptors increased significantly following NO synthase inhibition. Receptor affinity in the aorta decreased in the l -NAME group compared with control. However, uterine AngII receptor affinity was unchanged. 4. We conclude that the increased blood pressure and enhanced pressor responsiveness that occurs with chronic inhibition of NO synthesis may result partly from increased vascular AngII receptor expression.     

Decrease of GABA in the cerebrospinal fluid of patients with progressive myoclonus epilepsy and its correlation with the decrease of 5HIAA and HVA

The degenerative type of progressive myoclonus epilepsy (PME) is a hereditary disease with grand mal seizures, stimulus sensitive myoclonus, characteristic EEG and mental deterioration in the late stage. GABAergic antiepileptic drugs are the most effective ones in this disease, with an unknown etiology. In this study, the GABA concentration in the CSF of 15 PME patients was measured and compared with values of sex- and age-matched epileptic controls. It was correlated with the concentrations of 5HIAA and HVA in the CSF, which were determined earlier from the same patients. The GABA concentration in the PME patients was statistically significantly decreased, to about 75% of that of the epileptic controls. It correlated with HVA and 5HIAA concentrations in the PME patients, but not in the epileptic controls. It is unknown whether these findings are related to the primary cause of PME or whether they are only secondary, owing to a loss of respective neurons or synapses.     

Neuron-specific mitochondrial degeneration induced by hyperammonemia and octanoic acidemia

The neuropathological consequences of acute exposure to the neurotoxicants ammonia and octanoic acid were investigated with the isolated, perfused canine brain preparation. After 1 h of combined hyperammonemia and octanoic acidemia, ultrastructural changes were apparent in all brain regions examined. The cell bodies of neurons were the primary sites of these alterations. Neuronal mitochondria were distended, and the lamellae of the mitochondrial cristae were separated. In some cases the lamellae had completely dispersed, leaving only matrix remnants. Mitochondria of adjacent astrocytes appeared normal. Thus, a characteristic population of brain mitochondria is selectively vulnerable to a combination of hyperammonemia and octanoic acidemia and may be related to the biochemical mechanisms underlying encephalopathies of hepatic origin.     

Cardiovascular risk factors of young adults in relation to parental socioeconomic status: the Cardiovascular Risk in Young Finns Study

The socioeconomic status (SES) of the family influences the cardiovascular risk status of children and adolescents; however, it is not as well known whether parental SES has any effect on the risk factor profile of young adults. The aim of the present study was to investigate the relations of different aspects of parental SES, namely occupation, education, income and living area, to the common cardiovascular risk factors of their offspring (n = 919) aged 18, 21 and 24 years as a part of the Cardiovascular Risk in Young Finns Study in 1986. Subjects from farming families and rural areas had the highest serum total and low-density lipoprotein cholesterol values, and the lowest diastolic blood pressure compared with subjects from other occupational groups and subjects from urban regions. The diet of young adults from farming families and from rural areas contained more saturated fatty acids and less monounsaturated and polyunsaturated fatty acids. In addition, the body mass index was lower in subjects from urban regions compared with rural regions, and physical inactivity was less common in the urban group. Subjects with the highest parental occupational status smoked less compared with those with the lowest status. Parental education related inversely to physical inactivity and directly to dietary polyunsaturated fatty acids. The income level of the family associated positively with frequent inebriation by alcoholic beverages and inversely with the percentage of dietary energy from fat. In conclusion, there were modest inverse associations between different indicators of the SES of parents and some of the traditional risk factors of their offspring in young adulthood, which may contribute to the future risk of cardiovascular diseases.