5-Hydroxytryptamine-induced calcium-channel gating in rainbow trout (Oncorhynchus mykiss) peripheral blood lymphocytes.
The present study was conducted on peripheral blood lympho-cytes of rainbow trout (Oncorhynchus mykiss) to assess the role of 5-hydroxytryptamine (5-HT; 'serotonin') in calcium signalling. 5-HT-induced increases in intracellular free calcium concentrations, [Ca2+]i, and its action was mediated by 5-HT receptor subtype 3 (5-HT3), but not by 5-HT receptor subtype 1A (5-HT1A) or subtype 2 (5-HT2) in these cells. In Ca2+-containing medium (1 mM CaCl2), 5-HT and 2-methyl-5-HT (5-HT3 receptor agonist) induced increases in [Ca2+]i, whereas in Ca2+-free medium (0 Ca2+, 1 mM EGTA), these two agents failed to evoke increases in [Ca2+]i in these cells, demonstrating that 5-HT mobilizes Ca2+ from the extracellular environment. Furthermore, 5-HT-induced increases in [Ca2+]i are not contributed to by the intracellular endoplasmic reticulum (ER) pool, as thapsigargin, an agent that recruits Ca2+ from ER stores, had additive effects on 5-HT-induced [Ca2+]i responses in fish peripheral lymphocytes. 5-HT-induced increases in [Ca2+]i were mediated by 5-HT3 receptors via gating the calcium through L-type, but not N-type, calcium channels in trout lymphocytes.
Ferriere
F
F
Laboratoire de Physiologie, Unité d'Immunophysiologie Générale et Comparée, Université de Limoges, Faculté des Sciences, 123 Av. Albert Thomas, Limoges 87060, France.
Khan
N A
NA
Meyniel
J P
JP
Deschaux
P
P
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D015220:Calcium Channels / Q000097:blood*; D018492:Dopamine Antagonists / Q000494:pharmacology; D015640:Ion Channel Gating / Q000187:drug effects*; D015759:Ionomycin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D007650:Ketanserin / Q000494:pharmacology; D008214:Lymphocytes / Q000378:metabolism*; D008787:Metoclopramide / Q000494:pharmacology; D017686:Oncorhynchus mykiss; D012701:Serotonin / Q000031:analogs & derivatives / Q000494:pharmacology*; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013469:Sulpiride / Q000494:pharmacology
D015220:Calcium Channels; D018492:Dopamine Antagonists; D007476:Ionophores; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D012701:Serotonin; D015759:Ionomycin; C045918:2-methyl-5-HT; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D013469:Sulpiride; D007650:Ketanserin; D008787:Metoclopramide