Studies were carried out on the effects of Amaryllidaceae alkaloids and their derivatives upon herpes simplex virus (type 1), the relationship between their structure and antiviral activity and the mechanism of this activity. All alkaloids used in these experiments were biosynthesized from N-benzylphenethylamine; the apogalanthamine group was synthesized in our laboratory; those which may eventually prove to be antiviral agents had a hexahydroindole ring with two functional hydroxyl groups. Benzazepine compounds were neither cytotoxic nor antiviral, but many structures containing dibenzazocine were toxic at low concentrations. It was established that the antiviral activity of alkaloids is due to the inhibition of multiplication and not to the direct inactivation of extracellular viruses. The mechanism of the antiviral effect could be partly explained as a blocking of viral DNA polymerase activity.

Alkaloids↗

PubMedDate not supplied

CBF response to L-dopa influenced by peripheral decarboxylase inhibitor and serotonin in conscious SHR-SP, SHR-SR and WK rats.

1. L-Dopa induced a 56% increase in frontal cortical blood flow (fcCBF) one hour after intraperitoneal administration in stroke-prone spontaneously hypertensive rats. The treatment with carbidopa did not alter the magnitude of the response but shortened the response time to half an hour. In stroke-resistant rats and in Wistar Kyoto rats, L-dopa decreased fcCBF. This response was reversed to different degree by carbidopa pretreatment. 2. Serotonin decreased fcCBF in all groups. L-Dopa administered one hour after serotonin resulted in a recovery to the control level in SHR-SR, an increase in fcCBF in WK but the decreased flow in SHR-SP was maintained till the end of the observation time. 3. The data suggest that the stroke-prone rats have an unusual response to L-dopa and that L-dopa and this combination with a peripheral decarboxylase inhibitor may have a beneficial effect on the improvement of cerebral blood flow especially when the pre-existing level of cerebral blood flow is reduced in severe hypertension.

Animals↗

PubMedDate not supplied

Effect of dietary urea on blood pressure in spontaneously hypertensive rats.

The feeding of a normal diet containing 13.5% urea (in place of protein in a high protein diet) attenuated the development of severe hypertension and decreased the incidence of stroke in spontaneously hypertensive rats (SHR), when 1% NaCl solution was given to them. The urea not only increased urine volume, but also increased urinary sodium excretion in SHR given 1% NaCl for drinking. Although there was no obvious difference in erythrocyte size between the urea and the control groups, there was a significant inverse correlation between plasma urea level and erythrocyte size. These results suggest that a high protein diet reduced blood pressure partly through the diuretic effect of urea, the common metabolite of various proteins.

Animals↗

PubMedDate not supplied

Sodium preference and excretion in spontaneously hypertensive rats on various diets.

Stroke-prone spontaneously hypertensive rats (SHRSP) and stroke-resistant SHR (SHRSR) exhibited an increased preference for a 2% NaCl solution, relative to water, in comparison with normotensive Wistar-Kyoto (WKY), but the preference was lost quickly in SHRSP with unbroken exposure. Neither a high protein diet (50% fish protein) nor a low protein diet (5% protein) changed the salt water preference in SHRSR and the former abolished the preference more quickly in SHRSP. The fish protein diet, however, increased the ratio of urinary sodium excretion to dietary sodium intake in the first three days of exposure to a high salt intake in all groups. Results from this experiment suggest that an increased dietary protein intake can facilitate sodium excretion and may possibly ameliorate the adverse effect of a high sodium diet.

Animals↗

PubMedDate not supplied

Angiotensin II receptors in cardiac left ventricles of Dahl rats.

1. Dahl Iwai salt-sensitive (DS) rats have been reported as becoming hypertensive with left ventricular hypertrophy (LVH) and heart failure when on a high-salt diet. Their circulating renin-angiotensin system (RAS) has been reported to be suppressed. To evaluate the role of angiotensin II (AngII) type 1 and type 2 receptors (AT1 and AT2, respectively) in LVH, we compared cardiac AT1 and AT2 receptors in 10-week-old DS rats and Dahl Iwai salt-resistant (DR) rats. 2. Seven pairs of 6-week-old male DS and DR rats were fed either a low- or high-salt diet (0.3 or 8% NaCl, respectively) for 4 weeks. Left ventricular AngII receptors were measured by radioligand binding assays using [125I]-[Sar1,Ile8]-AngII in plasma membrane fractions from these four groups. The AT1 and AT2 receptors were distinguished using their specific antagonists CV 11974 and PD 123319, respectively. 3. The high-salt diet increased blood pressure and the left ventricle:bodyweight ratio in DS rats. However, neither Bmax for AT1 and AT2 receptors nor Kd for [125I]-[Sar1,Ile8]-AngII differed between the groups. These results are different from those of other reports of pressure-overload LVH, such as spontaneously hypertensive rats or renovascular hypertension rats, in which AT1 and AT2 receptors were reported to be up-regulated.

Animals↗

PubMedDate not supplied

Dietary effect on platelet aggregation in men with and without a family history of essential hypertension.

Platelet aggregation induced by 5 microM adenosine 5'-diphosphate (ADP) was significantly higher in men with a family history of essential hypertension than in men without such a history when they were fed a low fat-cholesterol diet with low salt. Platelet aggregation activity was remarkably increased in both groups when the diet was changed from low salt into high salt. Platelet aggregation activity was higher in the group with a positive family history of hypertension on the low fat-cholesterol plus high salt diet than in the group without a family history under the same conditions. The activity was slightly increased in both groups when fed a high fat-cholesterol diet with low salt. There was no significant difference in the platelet aggregation between the two groups. The activity was significantly increased in both groups on the high fat-cholesterol diet after the diet was changed from low salt to high salt. Under both the low and high fat-cholesterol diets, the mean blood pressure was significantly elevated in response to excessive salt intake in the group with a family history of essential hypertension, but it was not elevated in the group without such a family history.

Adenosine Diphosphate↗

PubMedDate not supplied

Interrelationships between blood pressure, sodium, potassium, serum cholesterol, and protein intake in Japanese.

Interrelationships among blood pressure (BP), sodium (Na), potassium (K), dietary protein, and serum cholesterol level (Chol) were examined in 62% (1120) of 1818 Japanese inhabitants of both sexes aged over 30 years who lived in a rural village in Japan. Fasting single-spot urine specimens were collected in the morning to measure Na, K, urea nitrogen (UN), inorganic sulfate (SO4), and creatinine (Cr). The Cr ratios of Na, K, UN, SO4, Na/K, and SO4/UN were analyzed by multiple regression analysis to determine independent associations with BP together with age, obesity index, hematocrit (Hct), Chol, triglyceride (TG), and fasting serum glucose level (Glu). Except for Na/Cr in men, Na/Cr and Na/K were found to be independently and positively related to BP, particularly to systolic BP (SBP). In contrast, K/Cr and SO4/UN (an index related to the dietary score of sulphur-containing amino acids derived mainly from animal protein) were both negatively associated with SBP, and UN/Cr (an index of total protein intake) was positively associated with SBP in men. Chol was linked to BP negatively in men but positively in women. Age, obesity index, TG, and Hct were generally positively and significantly related to BP in both sexes. The results confirmed on epidemiological grounds the positive link of Na and the negative link of K to BP within a single population in Japan. They further suggest, although only in men, that there is a negative relationship of Chol and dietary animal protein with BP.

Adult↗