The effects of serotonergic and dopaminergic lesions on sodium-sensitive [3H]mazindol binding in rat hypothalamus and corpus striatum.
The effects of intracerebroventricular administration of 6-hydroxydopamine (6-OHDA) and 5,7-dihydroxytryptamine (5,7-DHT) on sodium-sensitive [3H]mazindol binding were investigated in the rat hypothalamus and corpus striatum. In the hypothalamus, specific [3H]mazindol binding was inhibited by low concentrations of sodium and stimulated by high-sodium concentrations, whereas in the corpus striatum, only a sodium-dependent stimulation of [3H]mazindol binding was observed. Lesions with 6-OHDA significantly reduced sodium-dependent [3H]mazindol binding in the corpus striatum, but had no effect on the binding of [3H]mazindol in the absence of sodium. Lesions of serotonergic neurons with 5,7-DHT, however, had no effect on [3H]mazindol binding in the striatum, but resulted in a significant increase in the number of [3H]mazindol binding sites in the hypothalamus. These data suggest that [3H]mazindol may bind to two anatomically distinct binding sites, one that is stimulated and the other inhibited by sodium. The sodium-stimulated binding sites appear to be located on dopaminergic terminals in the striatum, and in the hypothalamus, the sodium-inhibited sites appear to be regulated by serotonergic neuronal activity.
Angel
I
I
Clinical Neuroscience Branch, NIMH, Bethesda, MD 20892.
Janowsky
A
A
Paul
S M
SM
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000502:physiology*; D006892:Hydroxydopamines; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D007211:Indoles / Q000378:metabolism*; D007276:Injections, Intraventricular; D008454:Mazindol / Q000378:metabolism*; D016627:Oxidopamine; D051381:Rats; D012701:Serotonin / Q000502:physiology*; D012964:Sodium / Q000494:pharmacology / Q000502:physiology*; D013574:Synaptosomes / Q000378:metabolism
D006892:Hydroxydopamines; D007211:Indoles; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D016627:Oxidopamine; D012964:Sodium; D008454:Mazindol; D004298:Dopamine