Reduced locomotor activity of rats mediated by peripheral beta adrenergic receptors.

The nonselective beta adrenergic agonist isoproterenol, the beta-2 selective agonist clenbuterol and, to a lesser extent, the beta-1 selective agonists dobutamine and prenalterol reduced locomotor activity of rats in a dose-dependent manner. These effects were antagonized by the beta adrenergic antagonist propranolol, suggesting mediation by beta adrenergic receptors. The hydrophilic beta adrenergic antagonist CGP-12177, which crosses the blood-brain barrier poorly, also blocked the effect of clenbuterol on locomotor activity with a potency similar to propranolol, suggesting that stimulation of peripheral beta adrenergic receptors is sufficient for reducing locomotor activity.