Comparative investigation on the cardio-protective action of the beta-blockers carazolol, propranolol and pindolol in rats.

A comparative study of the beta-receptor blockers propranolol, pindolol and carazolol, with respect to their cardio-protective properties against stress (hypoxia or isoprenaline injection) in rats showed the following. The beta-blockers investigated protected the heart against glycogen depletion during hypoxia. Carazolol was active at considerably lower doses than pindolol (about 25 times less) and propranolol (about 100 times later). All three beta-blockers protected against the induction of cardiac necroses by isoprenaline, but only carazolol produced almost complete protection. There is a good correlation between the protection against the development of cardiac necroses and the inhibition of tachycardia induced by isoprenaline (r = 0.96). The results are discussed from the point of view of the possible mechanisms by which the beta-blockers prevent cardiac damage induced by stress situations.