alpha-Adrenergic agents. 3. Behavioral effects of 2-aminotetralins

Studies with 5-substituted-8-methoxy-2-amino-tetralin compounds suggest that some are alpha 1-adrenoceptor agonists, which readily penetrate the blood-brain barrier. They potentiate the locomotor activity that is induced by apomorphine (AP) in reserpinized mice, an effect that has been suggested to result from activation of central alpha-receptors. This effect is selectively blocked by the preferential alpha 1-antagonist phenoxybenzamine, but not by drugs that block other types of receptors. The effect is also produced by the centrally administered alpha 1-agonists phenylephrine and methoxamine, but not by various types of standard CNS stimulants. When administered in high doses, some of the aminotetralin compounds induce locomotor activity in reserpinized mice without AP, an effect also found with high doses of centrally administered phenylephrine and methoxamine. This effect is blocked by a series of drugs at doses that correspond to their alpha 1-antagonist potencies.