Changes in noradrenergic terminal excitability induced by amphetamine and their relation to impulse traffic.

Article Details

Citation

Nakamura S, Tepper JM, Young SJ, Groves PM

Changes in noradrenergic terminal excitability induced by amphetamine and their relation to impulse traffic.

Neuroscience. 1982;7(9):2217-24. doi: 10.1016/0306-4522(82)90132-4.

PubMed ID
6292781 [ View in PubMed
]
Abstract

The effects of amphetamine upon the terminal excitability of noradrenergic neurons of the nucleus locus coeruleus were studied in urethane anesthetized rats. Terminal excitability was measured by determining the stimulus currents necessary to evoke antidromic responses in locus coeruleus neurons from terminals in the frontal cortex. In most cases, terminal excitability was decreased following local infusion of amphetamine into the frontal cortex, while intravenous administration of the drug tended to increase terminal excitability. The decreased terminal excitability induced by local infusion of amphetamine appeared to be due to activation of alpha-adrenergic receptors located on the terminals of locus coeruleus neurons, since this effect mimics that of clonidine, a direct acting alpha-adrenergic agonist, and since the effect was abolished by pretreatment with alpha-methyl-p-tyrosine which disrupts the catecholamine liberating properties of amphetamine. Phentolamine, a direct acting alpha-adrenergic receptor antagonist was also found to block or reverse the effect of amphetamine. The changes in terminal excitability following intravenous injection of amphetamine appeared to be related to changes in the spontaneous activity of locus coeruleus neurons. A large decrease in spontaneous activity following intravenous administration of amphetamine was associated with increased terminal excitability, whereas when smaller changes in spontaneous activity occurred, terminal excitability was found to be decreased. These results are discussed with respect to the pharmacological properties of catecholaminergic neurons and the mechanisms of action of amphetamine.

DrugBank Data that Cites this Article

Drug Targets
DrugTargetKindOrganismPharmacological ActionActions
DextroamphetamineAlpha adrenergic receptor (Protein Group)Protein groupHumans
Unknown
Inhibitor
Inducer
Details