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OBJECTIVES--To determine the anti-ischaemic effects of a new angiotensin converting enzyme inhibitor, benazepril, compared with nifedipine, alone and in combination, in chronic stable angina caused by coronary artery disease. DESIGN--Placebo controlled, double blind, latin square design. SETTING--Regional cardiology service for a mixed urban and rural population. SUBJECTS--40 patients with stable exertional angina producing at least 1 mm ST segment depression on exercise test with the Bruce protocol. 34 patients completed all four phases of the trial. INTERVENTIONS--Each patient was treated with placebo, benazepril (10 mg twice daily), nifedipine retard (20 mg twice daily), and a combination of benazepril and nifedipine in the same doses, in random order for periods of two weeks. MAIN OUTCOME MEASURES AND RESULTS--Total duration of exercise was not increased by any treatment. Exercise time to the development of 1 mm ST segment depression was not significantly changed with benazepril alone or in combination with nifedipine but was increased with nifedipine from 4.18 (1.8) min to 4.99 (1.6) min (95% confidence interval (95% CI) 0.28 to 1.34; p < 0.05). There was a significant relation between increase in duration of exercise and resting renin concentration (r = 0.498; p < 0.01). Myocardial ischaemia during daily activity, as assessed by ambulatory electrocardiographic monitoring, was reduced by benazepril and by the benazepril and nifedipine combination. This was significant for total ischaemic burden (451(628) min v 231(408) min; 95% CI -398 to -41 min; p < 0.05) and maximal depth of ST segment depression (-2.47(1.2) mm v -2.16 mm; 95% CI 0.04 to 0.57; p < 0.05) for the combination and for maximal ST segment depth for benazepril monotherapy (-2.47 (1.2) mm v -1.96(1.2) mm; 95% CI 0.18 to 0.91; p < 0.05). Benazepril significantly altered the circadian rhythm of cardiac ischaemia, abolishing the peak ischaemic periods at 0700 to 1200 and 1700 to 2300 (p < 0.05). CONCLUSIONS--Benazepril, an angiotensin converting enzyme inhibitor, had a modest anti-ischaemic effect in effort angina, but this effect was not as pronounced as with nifedipine. The anti-ischaemic action was more noticeable in asymptomatic ischaemia during daily activity, whereas nifedipine had little effect on this aspect of myocardial ischaemia. The combination of benazepril and nifedipine reduced ischaemia of daily activity. [ABSTRACT FROM PUBLISHER]

Two experimental paradigms were adopted to compare effects of scopolamine and its quaternary derivative, methylscopolamine, on the behaviour of albino rats in an exploration box comprising novel and familiar halves. Subjects tested with the first paradigm were exposed to one of the halves, injected and then observed 20 min later. Although both drugs reduced preferences for the previously inaccessible novel half, only scopolamine decreased rearing and increased ambulation. With the second paradigm, behaviour was assessed without any current drug influence. On the 2 days prior to testing the rats had been exposed to one half of the apparatus while drugged. Prior treatment with both scopolamine and methylscopolamine reduced novelty preference to the extent that the familiar half of the apparatus was preferred. Both drugs also reduced rearing (for females only) and ambulation. It was concluded that the results with both paradigms provided some support for the view that reductions in novelty preference by anticholinergic drugs arise from their aversive peripheral actions. [ABSTRACT FROM AUTHOR]