Uptake of 5-hydroxytryptamine in rat isolated atria.
1. The mode of 5-hydroxytryptamine (5-HT) uptake by the rat isolated atria was studied and compared to noradrenaline (NA) uptake. 2. Rat isolated atria were incubated with 14C-5-HT (46 microM) or 3H-NA 0.4 microM). After washing, the radioactivity fixed in atria was counted and the total NA, 5-HT and 5-hydroxyindol-3-acetic acid (5-HIAA) atria contents were measured by HPLC. 3. 14C-5-HT uptake was reduced in atria from 6-hydroxydopamine (100 mg/kg, i.p., 48 hr before experiments) or reserpine (2.5 mg/kg, i.p., 24 and 48 hr before experiments) pretreated rats. 4. The incubation of atria with 5-HT (50 microM) at the same time as 3H-NA reduced the 3H-NA value fixed. 5. Addition of desipramine (1 microM) or hydrocortisone (150 microM) before the incubation of atria with 14C-5-HT was without any effect on 14C-5-HT uptake. In contrast, fluvoxamine (1 microM) or indalpine (5 microM) caused a slight inhibition. 6. These data indicate that 5-HT is taken into the NA storage vesicles within the atria sympathetic nerves. This uptake does not use the NA carrier and involves partly the 5-HT carrier. An extraneuronal accumulation was noticed and a part of it is intracellular.
el Rawadi
C
C
Laboratoire de Pharmacologie, Faculté de Pharmacie, Châtenay-Malabry, France.
Heimburger
M
M
Davy
M
M
Midol-Monnet
M
M
Beslot
F
F
Cohen
Y
Y
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D006321:Heart / Q000187:drug effects; D006325:Heart Atria / Q000187:drug effects / Q000378:metabolism; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000378:metabolism
D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D009638:Norepinephrine