A neuronal basis for the alerting action of (+)‐amphetamine

Article date: July 1972

By: R. J. BOAKES, P. B. BRADLEY, J. M. CANDY in Volume 45, Issue 3, pages 391-403

(+)‐Amphetamine mimicked the excitatory and inhibitory actions of (—)‐noradrenaline on single neurones in the brain stem of acute halothane‐anaesthetized rats when these compounds were applied by iontophoresis. (+)‐Amphetamine had no actions on neurones unaffected by (—)‐noradrenaline.

These mimicking actions of (+)‐amphetamine could not be observed 20 h after treatment of the animals with reserpine 5 mg/kg.

The enzyme inhibitors α‐methyl‐p‐tyrosine and FLA 63 also greatly reduced the number of (—)‐noradrenaline‐mimicking responses to (+)‐amphetamine.

In animals pretreated with α‐methyl‐p‐tyrosine, but not in those pretreated with FLA 63, excitatory actions of (+)‐amphetamine on neurones excited by (—)‐noradrenaline could be elicited 45–90 min after systemic injection of l‐DOPA.

These results indicate that (+)‐amphetamine can release noradrenaline from presynaptic sites in the brain stem, which may be a basis for its alerting actions.

(+)‐Amphetamine mimicked the excitatory and inhibitory actions of (—)‐noradrenaline on single neurones in the brain stem of acute halothane‐anaesthetized rats when these compounds were applied by iontophoresis. (+)‐Amphetamine had no actions on neurones unaffected by (—)‐noradrenaline.

These mimicking actions of (+)‐amphetamine could not be observed 20 h after treatment of the animals with reserpine 5 mg/kg.

The enzyme inhibitors α‐methyl‐p‐tyrosine and FLA 63 also greatly reduced the number of (—)‐noradrenaline‐mimicking responses to (+)‐amphetamine.

In animals pretreated with α‐methyl‐p‐tyrosine, but not in those pretreated with FLA 63, excitatory actions of (+)‐amphetamine on neurones excited by (—)‐noradrenaline could be elicited 45–90 min after systemic injection of l‐DOPA.

These results indicate that (+)‐amphetamine can release noradrenaline from presynaptic sites in the brain stem, which may be a basis for its alerting actions.

DOI: 10.1111/j.1476-5381.1972.tb08096.x

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