| Title | Cocaine-Like Neurochemical Effects of Antihistaminic Medications. | | Author(s) | Tanda G, Kopajtic TA, Katz JL | | Institution | Psychobiology Section, Medications Discovery Research Branch, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA. | | Source | J Neurochem 2008 Mar 21. | | Abstract | The pattern of activation of dopamine neurotransmission in the nucleus accumbens (NAc) of rats produced by H(1) histamine antagonists which have behavioral effects like those of psychostimulant drugs was examined. Diphenhydramine and (+)-chlorpheniramine were compared to triprolidine, a potent and selective H(1) antagonist, and (-)-chlorpheniramine, which is less active than its enantiomer at H(1) receptors. Affinities of the drugs at DA, serotonin, and norepinephrine transporters, at H(1) receptors, and potencies for DA uptake inhibition in striatal synaptosomes were determined to assess mechanisms by which the compounds increased DA levels. Intravenous diphenhydramine (1.0-3.0 mg/kg), (+)- and (-)-chlorpheniramine (1.0-5.6 mg/kg), but not triprolidine (1.0-3.0 mg/kg) elicited a cocaine-like pattern of stimulation of DA transmission, with larger effects in the NAc shell than core. The absence of stereospecific effects with chlorpheniramine enantiomers, along with the lack of an effect with triprolidine suggest that the effects on DA transmission were not related to H(1) receptor antagonism. Although in vivo potencies were not directly related to DA transporter affinities, it is hypothesized that actions at that site, modulated by other actions, possibly those at the serotonin transporter, are primarily responsible for the neurochemical actions of the drugs on DA neurotransmission, and might underlie the occasional misuse of these medications. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 18363822 |
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