title: 5-Hydroxytryptamine release in dorsal hippocampus of freely moving rats: modulation by pindolol.
abstract: 1. The aim of the present study was to investigate the origin and modulation of 5-hydroxytryptamine release in dorsal hippocampus of freely moving rats using brain microdialysis. 2. Basal release of 5-hydroxytryptamine and 5-hydroxyindole-acetic acid was 3.0 +/- 0.2 pg/15 min and 519 +/- 18 pg/15 min, respectively. Stimulation by 60 mM K+ increased 5-hydroxytryptamine release by 66%. Inclusion of 10 microM tetrodotoxin in the perfusion medium reduced 5-hydroxytryptamine release to approximately 5% of basal levels. 3. In addition, release could be modulated by the 5-hydroxytryptamine receptor agonist 8-hydroxy-2-(di-N-propylamino)-tetralin (50 % decrease) and this effect was completely blocked by the 5-hydroxytryptamine-1 receptor antagonist pindolol. 4. These data are in concordance with results from the ventral hippocampus and indicate that release of 5-hydroxytryptamine is predominantly of neuronal origin. In contrast with other studies, the authors found the non-selective 5-hydroxytryptamine-1 antagonist, pindolol, to increase 5-hydroxytryptamine release by 65% following systemic administration. This may hint at a different autoreceptor control in serotonergic fibers ascending from the median raphe as compared to the dorsal raphe nucleus.
authors.affiliation: Department of Biological Psychiatry Academic Hospital Utrecht, The Netherlands.
authors.forename: F J
authors.initials: FJ
authors.lastname: Bosker
authors.forename: M G
authors.initials: MG
authors.lastname: Donker
authors.forename: A A
authors.initials: AA
authors.lastname: Klompmakers
authors.forename: K
authors.initials: K
authors.lastname: Kurata
authors.forename: H G
authors.initials: HG
authors.lastname: Westenberg
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010869:Pindolol / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology; D013997:Time Factors
chemical_list: D011985:Receptors, Serotonin; D012701:Serotonin; D013779:Tetrodotoxin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D010869:Pindolol; D011188:Potassium