Pronethalol hydrochloride is primarily used in medical research and pharmacology as a beta-adrenergic receptor antagonist. It is often employed in experimental studies to block the effects of adrenaline and noradrenaline on beta receptors, helping to understand cardiovascular and nervous system responses. This compound has been instrumental in early research on beta-blockers, contributing to the development of medications for conditions like hypertension, arrhythmias, and anxiety. Its use in clinical settings is limited due to the availability of more advanced beta-blockers, but it remains a valuable tool in laboratory studies for investigating adrenergic mechanisms.