Letter: Blood pressure, plasma renin activity, beta blockade and cardioselective beta-blocking drugs.
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Adrenergic beta-Antagonists↗
Biomedical subjects
K Haglund
Publications and source records attributed to K Haglund.
Plasma levels and effects of metoprolol on blood pressure, adrenergic beta receptor blockade, and plasma renin activity in essential hypertension.
The effects of metoprolol, a selective beta adrenergic receptor antagonist, on blood pressure, beta receptor blockade (antagoinst of isoproterenol and exercise tachycardia), and plasma renin activity (PRA) have been compared with those of placebo in 16 patients with essential hypertension. The dose of metroprolol was 25 mg three times daily for 1 wk and thereafter 100 mg three times daily for 5 wk. The mean decrease in blood pressure during treatment with metoprolol was 24 +/- 3.8 (SEM)/10 +/- 2.1 mm Hg in the lying position and 23 +/- 4.4/9 +/- 3.1 mm Hg after 1 min in the standing position. At a dose of 2.9 to 5.4 mg/kg, steady-state plasma concentrations of metoprolol varied 17-fold (from 20 to 341 ng/ml) between patients and correlated with the interindividual variability in isoproterenol antagonism (r = 0.58, p less than 0.05) and decrease in exercise tachycardia (r = 0.65, p less than 0.01). By contrast, neither of these variables correlated with the dose of metoprolol in mg/kg. Metoprolol decreased PRA by 67 +/- 1.9 and 71 +/- 1.2% in the lying and standing positions, respectively. The decrease in the mean arterial blood pressure in the lying position was significantly correlated to the PRA during the placebo period (r = 0.61, p less than 0.05) but not to the plasma steady-state levels of metoprolol, the degree of beta receptor blockade, and the decrease in PRA.
Adrenergic beta-Antagonists↗
The military way.
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Education, Medical, Graduate↗
The occupational hazards of a medical education: hospitals and medical school laboratories are very complex places to work.
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District of Columbia↗
Effects of paired and unpaired eye-blink conditioning on Purkinje cell morphology.
This experiment addressed (1) the importance of conjunctive stimulus presentation for morphological plasticity of cerebellar Purkinje cells and inhibitory interneurons and (2) whether plasticity is restricted to the spiny branches of Purkinje cells, which receive parallel fiber input. These issues were investigated in naive rabbits and in rabbits that received paired or unpaired presentations of the conditioned stimulus (CS) and unconditioned stimulus (US). To direct CS input to the cerebellar cortex, pontine stimulation served as the CS. Air puffs to the cornea served as the US. Paired condition rabbits received pontine stimulation for 350 msec paired with a coterminating 100-msec air puff. Unpaired condition rabbits received the same stimuli in a pseudorandom order at 1- to 32-sec intervals. Rabbits were trained for a mean of 12 days. Naive rabbits received no treatment. In Golgi-stained Purkinje neurons in lobule HVI, total dendritic length, main branch length, total spiny branch length, and number of spiny branch arbors were all greater in the naive group than in the paired and unpaired groups, which did not differ. No differences were found between the hemispheres ipsilateral and contralateral to the trained eye. The dendritic length and number of branches for inhibitory interneurons did not differ across groups. The Purkinje cell morphological changes detected with these methods do not appear to be uniquely related to the conjunctive activation of the CS and US in the paired condition.
Animals↗