Serotonin induces a decrease of 5-HT(1A) immunoreactivity in organotypic hippocampal cultures.
Serotonin reuptake inhibitors used for the treatment of depression act by increasing serotonin levels at the synaptic cleft and thereby activating 5-HT(1A) serotonin receptors. However, the effect of increased levels of serotonin on postsynaptic 5-HT(1A) receptor density is unknown. The purpose of this study was to investigate, in a culture model, how postsynaptic 5-HT(1A) receptors are influenced by serotonin. Different concentrations of serotonin (0.5, 1, 10, 50 and 100 microM) were added to organotypic hippocampal cultures and incubated for 1 week. The cultures were immunostained for the 5-HT(1A) receptor and the staining analyzed densitometrically. 5-HT(1A) levels decreased with increasing serotonin concentrations, being significant at 10, 50 and 100 microM. These results indicate that at increasing serotonin levels the density of postsynaptic 5-HT(1A) receptors is down-regulated.
Aznar
S
S
Neurobiology Research Unit, Copenhagen University Hospital, Unit 9201, Blegdamsvej 9, 2100 Copenhagen, Denmark.
Knudsen
G M
GM
D000818:Animals; D000906:Antibodies; D003712:Dendrites / Q000378:metabolism; D003863:Depression / Q000378:metabolism; D005452:Fluoresceins; D005456:Fluorescent Dyes; D006624:Hippocampus / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D007150:Immunohistochemistry; D008869:Microtubule-Associated Proteins / Q000032:analysis; D009924:Organ Culture Techniques; D009930:Organic Chemicals; D051381:Rats; D011985:Receptors, Serotonin / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D044263:Receptors, Serotonin, 5-HT1; D012701:Serotonin / Q000494:pharmacology*
D000906:Antibodies; D005452:Fluoresceins; D005456:Fluorescent Dyes; D008869:Microtubule-Associated Proteins; D009930:Organic Chemicals; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; C435731:fluoro jade; D012701:Serotonin