A pharmacodynamic study on clenbuterol-induced toxicity: beta(1)- and beta(2)-adrenoceptors involvement in guinea-pig tachycardia in an in vitro model

Beta(2)-receptor adrenergic agonists as clenbuterol and analogues are illegally used as growth promoters in cattle, in Europe, as well as in other countries. We investigated whether heart rate increase induced by clenbuterol could depend upon stimulation of beta(1)- and/or beta(2)-adrenergic receptors, and in which ratio