Dichloro-isoprenaline

Dichloro-isoprenaline was the first [3-adrenoceptor antagonist to he described (6). It was discovered in a search for specific (3-stimulants as bronchodilators. This compound is a partial agonist, i.e. it can antagonise the action of isoprenaline hut itself is a (3-stimulant. (The stimulant action of dichloro-isoprenaline is readily demonstrated in an animal depleted of natural catecholamines ( with say reserpine). In this type of preparation it will stimulate say heart rate to a maximum of 70% of that produced hy isoprenaline itself). 

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