Potentiation of d-amphetamine and l-dopa-induced acoustic startle activity after long-term exposure to amphetamine

Abstract

The startle response to an auditory atimulus was potentiated by treatment with d-amphetamine sulfate. Administration of l-dopa after pretreatment with the extracerebral decarboxylase inhibitor MK-486 also increased startle activity. After long-term exposure to amphetamine the startle response to l-dopa and d-amphetamine was enhanced. These findings are consistent with the consequences of longterm amphetamine administration on other amphetamine-induced behaviors (e.g. stereotypy), and are discussed in terms of the effects of long-term amphetamine treatment on pre-and postsynaptic dopamine receptors and serotonin.