Gene/Protein Disease Symptom Drug Enzyme Compound
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 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxprenolol is a beta-adrenergic blocker with intrinsic sympathomimetic activity. Such drugs are not currently available in the United States, although they have the advantage of less negative inotropic effect than the available propranolol. In 18 patients with mild essential hypertension, oxprenolol (9 patients) or propranolol (9 patients) was added to thiazide in random double-blind fashion and continued for 7 wk during which supine heart rate, blood pressure, and noninvasively measured cardiac output (by CO2 rebreathing) were determined weekly. With thiazide dosage constant throughout, maximal dose titration to 386. +/- 52.1 (SEM) mg/day of oxprenolol and 360.0 +/- 45.4 mg/day of propranolol was achieved over the first 5 wk. Blood pressure fell with both (141.8 +/- 4.8/96.0 +/- 2.3 to 128.0 +/- 5.1/87.2 +/- 1 mm Hg on oxprenolol, p less than 0.01; 150.8 +/- 5.5/98.0 +/- 1.7 to 129.9 +/- 5.5/86.8 +/- 3.4 mm Hg on propranolol, p less than 0.01). Cardiac output fell from 6.85 +/- 0.63 to 5.77 +/- 0.45 1/min (p less than 0.01) on oxprenolol, and from 6.79 +/- 0.61 to 5.37 +/- 0.37 1/min (p less than 0.02) on propranolol. Oxpranolol. Oxprenolol reduced heart rate from 76.4 +/- 2.0 to 65.6 +/- 2.1 beats/min (p less than 0.001) and it fell from 82.0 +/- 3.8 to 65.3 +/- 3.7 beats/min (p less than 0.001) with propranolol; the fall in heart rate was less but not significantly so for oxprenolol (-14.2 +/- 1.8% and -19.8 +/- 2.8%, p less than 0.1). Thus oxprenolol is equivalent to propranolol in antihypertensive action; minor hemodynamic differences between the two drugs might reflect intrinsic sympathomimetic activity of oxprenolol. Oxprenolol should be considered as an alternative to propranolol.
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PMID:Hemodynamic effects of oxprenolol and propranolol in hypertension. 38 30

The effect of beta-adrenoceptor antagonists, with and without intrinsic sympathomimetic activity, on the regulation of lymphocytic beta adrenoceptors during acute physical exercise was studied. Seven healthy volunteers underwent a graded maximal ergometer test after treatment for 7 days with placebo, propranolol (2 x 80 mg/day), or pindolol (2 x 10 mg/day). Each subject received the three types of drug treatment in a double-blind, randomized fashion, with 3 weeks wash-out periods between the on-drug periods. The mean resting density of lymphocytic beta adrenoceptors was 46 +/- 5 fmol/mg protein (mean +/- SEM) during placebo, 53 +/- 5 fmol/mg protein during propranolol, and 29 +/- 4 fmol/mg protein during pindolol treatment (p less than 0.05, pindolol vs. propranolol). Exercise induced a significant up-regulation of the beta-adrenoceptor density during each treatment modality, but the increment was attenuated during propranolol (mean elevation, 16 +/- 2 fmol/mg protein, p less than 0.05) and pindolol intake (13 +/- 4 fmol/mg protein, p less than 0.02) as compared with the placebo value (56 +/- 13 fmol/mg protein). Moreover, exercise-induced increment of lymphocytic cyclic AMP (cAMP) production was virtually abolished by the two beta-adrenoceptor antagonists. In conclusion, administration of beta-adrenoceptor antagonists is associated with a subnormal up-regulation of the lymphocytic beta-adrenoceptors and alterations in their functioning during heavy physical effort. This attenuation is not modified by intrinsic sympathomimetic activity of the compound.
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PMID:Effect of propranolol and pindolol on the up-regulation of lymphocytic beta adrenoceptors during acute submaximal physical exercise. A placebo-controlled double-blind study. 169 82

Enzymatically inactive renin (IR) is the predominant circulating form of renin. Sympathetic activity may influence plasma renin activity (PRA) by regulation of the conversion of IR to active renin (AR, PRA). It has been demonstrated previously that beta blockade lowers PRA at least partly through inhibition of this conversion process. The authors hypothesized that beta blockade and intrinsic sympathomimetic activity (ISA) would have opposing effects on production of AR from its inactive precursor. Eighteen primary hypertensives (12 male, 6 female, mean age 57.7 +/- 2.7) were entered in a placebo-controlled, double-blind crossover study of the effects of equipotent doses of pindolol and propranolol on mean +/- SEM systolic BP, diastolic BP, heart rate, active renin (AR), total renin (TR), inactive renin (IR), and % AR/TR. Drug dose was titrated to achieve a goal DBP of 90 mmHg or less. Active renin was defined as the rate of generation of angiotensin I in 37 degrees C plasma at pH 5.7. Total renin was determined by preincubation of plasma aliquots with 1.5 mg/mL trypsin in the presence of 5 mM benzamadine for one hour at -4 degrees C prior to assay of renin activity. Inactive renin was calculated as TR minus AR. The BP responses achieve by dose titration of propranolol and pindolol were virtually identical at rest, indicating equivalent depressor effects of the two beta blockers. Heart rate and active renin were, however, lowered to a much greater extent with propranolol as compared with pindolol. The lack of significant pindolol-induced fall in % AR/TR suggests that this drug has little net effect on the formation of AR from IR.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Intrinsic sympathomimetic activity counteracts beta-blocker inhibition of renin activation. 256 12

1. In order to evaluate the mechanism by which beta blockers with intrinsic sympathomimetic activity preserve left ventricular systolic function at rest, 46 patients with coronary artery disease were studied by right and left heart catheterization and left ventriculography. Patients were studied using a double-blind, randomized protocol before and after a single intravenous dose of 3 mg propranolol (N = 22) or 0.5 mg pindolol (N = 24). 2. Mean right atrial pressure increased similarly after both drugs. Mean pulmonary artery pressure, left ventricular end-diastolic pressure, mean aortic pressure, and peripheral vascular resistance did not change significantly after either drug. Cardiac index (before: 3.0 +/- 0.7 (mean +/- SEM); after: 2.8 +/- 0.2 1 min-1 m-2) and heart rate (before: 78 +/- 15; after: 72 +/- 12 bpm) decreased only after propranolol administration. 3. Ejection fraction decreased only after propranolol (48 +/- 16 to 41 +/- 15%). Improvement in segmental wall motion abnormalities was noted (23 of 47 segments) only after pindolol. The total left ventricular wall motion score improved after pindolol and worsened after propranolol (P less than 0.05). In patients with impaired left ventricular function, pindolol administration resulted in improved resting ejection fraction. 4. Thus, the acute hemodynamic consequences of pindolol administration differ from those of propranolol owing to the preservation of left ventricular systolic function which seems to be related to the intrinsic sympathomimetic effect of pindolol on areas of reversible wall motion abnormality.
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PMID:Improvement in wall motion after pindolol: a mechanism for the preservation of left ventricular function in coronary artery disease. 269 44

In six patients with hypertriglyceridaemia presenting whilst receiving treatment with beta-adrenoreceptor blocking drugs (mean serum triglycerides 31.2 mmol/l) the half-life (t1/2) of an intravenously administered triglyceride emulsion was 32.8 +/- 7.9 min (mean +/- SEM) on beta-blocker and 22.8 +/- 4.8 min after stopping beta-blocker treatment. In three of these patients subsequent administration of a beta-blocker with intrinsic sympathomimetic activity had no effect on t1/2. In a cross-over trial of placebo, atenolol (beta 1-blocker), propranolol (beta 1- and beta 2-blocker) and pindolol (beta 1- and beta 2-blocker with intrinsic sympathomimetic activity) in 11 normal men t1/2 was 11.8 +/- 0.9, 12.6 +/- 1.1, 14.3 +/- 1.7 and 12.4 +/- 1.1 min respectively. None of the apparent differences achieved statistical significance, but in two men marked increases in t1/2 occurred on propranolol. The concentrations of serum triglycerides and very low density lipoprotein cholesterol in the normal men were, however, increased by beta-blockade, most markedly by pindolol. Serum high density lipoprotein (HDL) cholesterol concentration decreased in normal men on beta-blockers, most clearly on atenolol and propranolol. This decrease was due to a reduction in cholesterol in the HDL2 subfraction. No statistically significant effects on serum low density lipoprotein cholesterol or apolipoprotein B concentrations occurred in the normal men. The doses of atenolol and propranolol used in this study were equipotent as judged by the heart rate response to exercise.
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PMID:Short-term effects of beta-adrenoceptor blocking drugs with and without cardioselectivity and intrinsic sympathomimetic activity on lipoprotein metabolism in hypertriglyceridaemic patients and in normal men. 286 62

Previous studies have indicated that some hypertensive patients, following a period of effective treatment with certain antihypertensive drugs, may experience prolonged normotension after drug withdrawal. We have studied the ability of carteolol, a nonselective beta-adrenoceptor antagonist with intrinsic sympathomimetic activity, to produce such remissions of hypertension. Thirty-four patients whose diastolic blood pressure was controlled at 90 mm Hg or less with carteolol monotherapy (2.5 to 5.0 mg/d for an average of 328 days) were randomized to a nine-month, double-blind, placebo-controlled drug-withdrawal trial. Those patients randomized to continue carteolol therapy had initially responded to carteolol treatment with reduction in blood pressure from 151 +/- 4/99 +/- 2 to 132 +/- 4/80 +/- 2 mm Hg. Those randomized to treatment with placebo had initially responded with blood pressure reductions from 154 +/- 4/97 +/- 2 to 137 +/- 4/81 +/- 2 mm Hg. Changes in mean systolic and diastolic blood pressure (mm Hg +/- SEM) from baseline during carteolol therapy to the final visit at nine months were not different for patients receiving placebo (13 +/- 5/6 +/- 4 mm Hg, recumbent; 11 +/- 6/4 mm Hg, standing) or carteolol (11 +/- 5/7 +/- 3 mm Hg, recumbent; 12 +/- 6/7 +/- 3 mm Hg, standing). The final mean recumbent diastolic blood pressure (86.9 mm Hg) was the same in both groups. Prolonged normotension may follow a period of carteolol treatment, again suggesting the potential importance of periodic withdrawal of antihypertensive medication.
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PMID:Remission of mild to moderate hypertension after treatment with carteolol, a beta-adrenoceptor blocker with intrinsic sympathomimetic activity. 304 36

The local hemodynamic effect of pindolol, a nonselective beta-blocker with intrinsic sympathomimetic activity, was investigated in 17 healthy volunteers. Changes in forearm blood flow (FBF) in response to infusion of drugs into the brachial artery were measured by plethysmography. Pindolol increased FBF dose dependently to a maximal value of 62 +/- 8% (mean +/- SEM, p less than 0.001) without inducing changes in heart rate or blood pressure. For a single dose of pindolol the maximal effect on FBF was seen after approximately 4 minutes of infusion, and this effect persisted for at least 12 minutes after the infusion. The pindolol-induced increase in FBF was reduced by concomitant infusion of propranolol (p less than 0.001). Intra-arterial infusion of practolol did not influence FBF. No significant influence of pindolol was found on the vasoconstriction induced by the alpha 1-adrenergic receptor agonist methoxamine, the alpha 2-adrenergic receptor agonist BHT-933, or angiotensin II. Measurement of plasma pindolol concentrations in the venous effluent of the forearm suggested that vasodilatation occurred at drug levels within the therapeutic range. These results indicate that the beta-blocker pindolol has vasodilatory properties owing to stimulation of vascular beta 2-adrenergic receptors and that this effect may be of therapeutic relevance.
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PMID:Acute vasodilator action of pindolol in humans. 398 56

Continuous monitoring of blood glucose concentration was compared with frequent intermittent sampling in 12 non-diabetic adult patients undergoing open-heart surgery with cardiopulmonary by-pass using priming fluids free of glucose. Continuous monitoring revealed several changes which were not detected on intermittent sampling. Blood glucose concentration decreased by 2 mmol litre-1 +/- 0.5 (SEM) (P less than 0.01) immediately on the institution of CPB, and increased during the succeeding minutes. Rewarming from hypothermic by-pass was associated with a 3 (+/- 0.5)-mmol litre-1 increase in blood glucose concentration (P less than 0.01). Commencement of infusions of sympathomimetic agents resulted in a similar increase.
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PMID:Continuous monitoring of blood glucose concentration during open-heart surgery. 400 97

Although right ventricular function may be examined by following the passage (first pass) of a bolus of radionuclide through the right heart before it reaches the left heart, the counts detected with conventional gamma cameras in such a short time interval are low; moreover, repeated determinations would result in an unacceptable radiation burden to the patient. We have modified the gated equilibrium blood pool method to allow repeated assessment of the right ventricular ejection fraction (RVEF) and have compared the results with the first-pass method in 43 patients. Good agreement was obtained between the two methods (r = 0.91, p less than 0.001). The mean difference between the two methods was 0.04 with an intra-observer variation for the equilibrium studies of 0.03 and an inter-observer difference of 0.04. The mean difference in RVEF for seven patients studied on two separate occasions 30 minutes apart was only 0.02. In four patients the mean RVEF measured at rest was 0.44 +/- 0.05 (SEM) and after exercise it was 0.48 +/- 0.06. After infusion of isoprenaline at 1 microgram/min the mean rose to 0.64 +/- 0.04 (p less than 0.02) and after infusion of a new beta 1-sympathomimetic agent, prenalterol, at doses of 1 and 2 mg it was 0.56 +/- 0.02 (p less than 0.02) and 0.59 +/- 0.03 (p less than 0.01) respectively, where the significance levels are relative to the resting values. In nine patients with good ventricular function the vasodilator nifedipine caused right and left ventricular ejection fractions to increase by the same amount; while in six patients with severe impairment of left ventricular function due to ischaemic heart disease the RVEF increased from 0.58 +/- 0.03 to 0.73 +/- 0.03 (p less than 0.01) after 2 mg of prenalterol, but the left ventricular ejection fraction increased only from 0.22 +/- 0.04 to 0.26 +/- 0.04. We conclude that repeated estimation of right ventricular performance is possible by equilibrium radionuclide ventriculography.
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PMID:Can right ventricular performance be assessed by equilibrium radionuclide ventriculography? 613 86

Eight out-patients with essential hypertension participated in a comparative, placebo-controlled study with a cross-over design. Pindolol and propranolol were administered orally in doses of 20.0 +/- 3.13 mg/d (mean +/- SEM) and 125.0 +/- 19.17 mg/d respectively. Pindolol reduced mean blood pressure by 11.9 mmHg; pre-ejection period index by 8.1 msec; total peripheral resistance by 3.1 mmHg min/L; and limb vascular resistance by 3.28 mmHg min 100 g/ml. Heart rate, cardiac output, plasma renin activity and urinary norepinephrine excretion rate were not altered by pindolol. Propranolol reduced mean blood pressure by 14.0 mmHg; heart rate by 9.1 beats/min; cardiac output by 0.57 L/min; limb blood flow by 1.06 ml/100 g.min; and plasma renin activity by 1.44 ng/ml/h; and increased pre-ejection period index by 8.7 msec. Total peripheral resistance, limb vascular resistance and urinary norepinephrine excretion rate were not altered by propranolol. It was concluded that: (1) the drugs, pindolol and propranolol, are equally effective as antihypertensive agents; (2) heart function and plasma renin activity are decreased by propranolol and unaltered by pindolol; (3) total peripheral resistance is decreased by pindolol and unaltered by propranolol; and (4) these findings may be explained by the intrinsic sympathomimetic activity exhibited by pindolol only.
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PMID:A comparative study on the effects of pindolol and propranolol on systemic and cardiac haemodynamics in hypertensive patients. 638 72


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