The effect of amphetamine and L‐dopa on tetrabenazine‐induced suppression of intracranial self‐stimulation in the rat

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Abstract
Abstract.— The administration of d‐amphetamine sulphate resulted in a restoration of intracranial self‐stimulation (ICSS) suppressed by tetrabenazine (TBZ). A dose‐dependent increase in the rate of ICSS was seen after l‐dopa in animals pretreated with TBZ. d‐Amphetamine is believed to act by facilitating the nerve‐impulse induced release of central catecholamines (CA) whereas the blockage of the granular uptake‐storage mechanism by TBZ will prevent the storage of CA formed from the administrated l‐dopa and thereby interfere with their release by nerve‐impulses. Thus, in the latter case, an activation of central CA receptors in all probability will be due to a dose‐dependent diffusion of CA from nerve terminals. It is suggested that the failure to completely antagonize the TBZ‐induced suppression of behaviour by l‐dopa is due to the fact that a direct activation, independent of the nerve‐impulse flow, of central CA receptors easily results in an overstimulation and a reduced specificity in behaviour.