Additive effects of apomorphine and clonidine on serotonin neurons in the dorsal raphe. 1987

E H Lee

Effects of apomorphine (APO) and clonidine (CLON) on the mesostriatal and mesolimbic serotonergic systems were examined in the present study. Both drugs selectively elevated serotonin (5-HT) concentrations in the dorsal raphe and the striatum without significantly altering 5-HT measures in the median raphe and the hippocampus. Apomorphine also increased tryptophan and 5-hydroxyindoleacetic acid (5-HIAA) levels in the dorsal raphe and 5-HIAA level in the striatum. Clonidine did not markedly alter tryptophan and 5-HIAA measures, while it decreased 5-HT turnover rate in both region, as indicated by the ratio of 5-HIAA/5-HT levels. Co-administration of APO and CLON, at doses of each drug exerted maximum effects on 5-HT alone, produced an additive effect on 5-HT in the dorsal raphe, while their effects on 5-HT and 5-HIAA in the striatum were counteracting each other. Effects of APO on 5-HT and 5-HIAA were attributed to the elevation of 5-HT precursor tryptophan, while effects of CLON on 5-HT and 5-HIAA were due to a decreased rate of 5-HT turnover. Therefore, the present results support the hypothesis that the additive effects of APO and CLON on dorsal raphe 5-HT are mediated through different receptors and neuropharmacological mechanisms.

UI MeSH Term Description Entries
D008297 Male Males
D009474 Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM. Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D011903 Raphe Nuclei Collections of small neurons centrally scattered among many fibers from the level of the TROCHLEAR NUCLEUS in the midbrain to the hypoglossal area in the MEDULLA OBLONGATA. Caudal Linear Nucleus of the Raphe,Interfascicular Nucleus,Nucleus Incertus,Rostral Linear Nucleus of Raphe,Rostral Linear Nucleus of the Raphe,Superior Central Nucleus,Central Nucleus, Superior,Incertus, Nucleus,Nuclei, Raphe,Nucleus, Interfascicular,Nucleus, Raphe,Nucleus, Superior Central,Raphe Nucleus
D011919 Rats, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding. August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D003000 Clonidine An imidazoline sympatholytic agent that stimulates ALPHA-2 ADRENERGIC RECEPTORS and central IMIDAZOLINE RECEPTORS. It is commonly used in the management of HYPERTENSION. Catapres,Catapresan,Catapressan,Chlophazolin,Clofelin,Clofenil,Clonidine Dihydrochloride,Clonidine Hydrochloride,Clonidine Monohydrobromide,Clonidine Monohydrochloride,Clopheline,Dixarit,Gemiton,Hemiton,Isoglaucon,Klofelin,Klofenil,M-5041T,ST-155,Dihydrochloride, Clonidine,Hydrochloride, Clonidine,M 5041T,M5041T,Monohydrobromide, Clonidine,Monohydrochloride, Clonidine,ST 155,ST155
D004305 Dose-Response Relationship, Drug The relationship between the dose of an administered drug and the response of the organism to the drug. Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D006624 Hippocampus A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation. Ammon Horn,Cornu Ammonis,Hippocampal Formation,Subiculum,Ammon's Horn,Hippocampus Proper,Ammons Horn,Formation, Hippocampal,Formations, Hippocampal,Hippocampal Formations,Hippocampus Propers,Horn, Ammon,Horn, Ammon's,Proper, Hippocampus,Propers, Hippocampus,Subiculums
D006897 Hydroxyindoleacetic Acid 5-HIAA,5-Hydroxy-3-Indoleacetic Acid,5-Hydroxyindolamine Acetic Acid,5 Hydroxy 3 Indoleacetic Acid,5 Hydroxyindolamine Acetic Acid,Acetic Acid, 5-Hydroxyindolamine,Acid, 5-Hydroxy-3-Indoleacetic,Acid, 5-Hydroxyindolamine Acetic,Acid, Hydroxyindoleacetic
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D001058 Apomorphine A derivative of morphine that is a dopamine D2 agonist. It is a powerful emetic and has been used for that effect in acute poisoning. It has also been used in the diagnosis and treatment of parkinsonism, but its adverse effects limit its use. Apokinon,Apomorphin-Teclapharm,Apomorphine Chloride,Apomorphine Hydrochloride,Apomorphine Hydrochloride Anhydrous,Apomorphine Hydrochloride, Anhydrous,Apomorphine Hydrochloride, Hemihydrate,Britaject,Apomorphin Teclapharm

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