Behavior and binding: desensitization to alpha 1-adrenergic stimulation of acoustic startle is associated with a decrease in alpha 1-adrenoceptor binding sites

Desensitization of the excitatory effects of alpha 1-adrenergic agonists on acoustic startle occurred 6 h after intrathecal administration of the alpha 1-adrenergic agonist, phenylephrine. This desensitization was associated with a decrease in alpha 1-adrenoceptor sites in the lumbar spinal cord.