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The comparison of two measurements of the pigeon threshold for electrical stimuli, performed 2 h apart, reveals stress-induced analgesia as a result of stressful manipulations between the two tests. When pigeons are exposed to a weak, oscillating magnetic field between the two measurements, the analgesic response is inhibited and a hyperalgesic effect is recorded. The present findings are in agreement with previous studies showing that magnetic treatments may alter pigeons' emotional state and some of their behavioral patterns.

It has been recognized as increasingly important to determine whether antihypertensive agents, while satisfactorily lowering the blood pressure, at the same time adversely or positively affect the cardiac hemodynamic profile. On theoretical grounds, one would expect that an ideal hypotensive drug should decrease blood pressure by decreasing total peripheral resistances, without affecting cardiac output, and should normalize left ventricular hypertrophy without deteriorating systolic or diastolic left ventricular function. We here briefly review the effects of urapidil on these variables in patients under chronic treatment investigated in a series of studies employing echocardiography. The results of the studies are in fair agreement and indicate a blood pressure decrease already after one month of treatment, due to a decrease of peripheral resistances, without changes in heart rate. A clear trend towards a reduction of cardiac hypertrophy during the treatment is suggested by the significant decrements of the indices measured. One study also suggests that right ventricular wall thickness may be reduced. Left ventricular dimensions remained unchanged in all except one study. Systolic and diastolic function indices were also unchanged during the first 6 months of treatment and, in one study, improvement was found after 12 months of treatment. Taken together these results suggest that urapidil lowers blood pressure favorably, affecting cardiac morphology and function.

The aim of this study was to evaluate if Doppler indexes of left ventricular filling are related to exercise capacity. Since a correlation between left ventricular filling pattern and causal blood pressure has been recently reported along a wide range of pressure values, a group of subjects with blood pressure ranging from normal to severely elevated values was studied. Twenty-four subjects (11 normotensives, 13 mild to severe hypertensive patients) underwent an echo-Doppler study and a maximal multistage cycloergometric exercise test. Since the cycloergometric test was limited by fatigue or dyspnea in all subjects, exercise duration was used as an effort tolerance index. Echocardiographic indexes of systolic function resulted normal in all subjects. Significant relationships with exercise duration were found for several indexes of left ventricular filling (A peak: r = -.743, p.0001; A/E ratio: r = -.606, p.005; early filling fraction: r = .639, p.001). Exercise time was also significantly related to casual blood pressure, both systolic and diastolic. The relationships between transmitral blood flow and exercise capacity seem to indicate that an impairment of ventricular relaxation (as indicated by the progressive increase of atrial contribution) is associated with a decreased exercise tolerance, possibly because a progressively lower activation of Frank-Starling mechanism. Diastolic function thus seems to be able to affect exercise tolerance even in subjects with normal systolic function and blood pressure ranging from normal to severely elevated values.