Intraventricular galanin produces a time-dependent modulation of 5-HT1A receptors in the dorsal raphe of the rat.
Galanin given i.c.v. increased the K(D) values of 5-HT1A receptors in the DR by 100% 10 min after administration. This effect had disappeared 2 h and 5 h after galanin administration. In contrast, i.c.v. galanin caused a 40% increase in the Bmax values at 2 h without affecting the Bmax values 10 min and 5 h after i.c.v. galanin. The mRNA levels of 5-HT1A receptors and of galanin in the DR were significantly decreased by 33% and 56% respectively 2h but not 5h after i.c.v. galanin. These results suggest that in vivo galanin can modulate somatodendritic 5-HT1A receptors in the DR in a time-dependent manner via galanin-5-HT1A receptor interactions. The findings implicate a potential role of galanin in affective disorders.
Razani
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Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
Diaz-Cabiale
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Fuxe
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Ogren
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D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites / Q000187:drug effects / Q000502:physiology; D004334:Drug Administration Schedule; D019004:Galanin / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D011869:Radioligand Assay / Q000706:statistics & numerical data; D011903:Raphe Nuclei / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000187:drug effects* / Q000378:metabolism*; D044263:Receptors, Serotonin, 5-HT1; D013997:Time Factors; D014316:Tritium
D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D014316:Tritium; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D019004:Galanin