Serotonin elevates intracellular Ca2+ in rat choroid plexus epithelial cells by acting on 5-HT2C receptors.
The effects of serotonin (5-HT) on intracellular calcium activity ([Ca2+]i) in epithelial cells from rat choroid plexuses were examined. Experiments were performed on isolated cells which had been maintained in primary culture. ([Ca2+]i) was measured using micro-spectrofluorimetric techniques and the fluorescent indicator Fura-2. 5-HT was found to increase [Ca2+]i in a dose dependent manner. The [Ca2+]i response was biphasic, with an initial peak of [Ca2+]i (due to release from intracellular stores), followed by an elevated plateau phase (the result of calcium influx). The effect of 1 microM 5-HT was inhibited by mesulergine and mianserin (50 nM), which are antagonists of the 5-HT2C receptor. Spiperone and ketanserin (200 nM), less specific 5-HT2 receptor blockers, caused only a slight reduction in the response to 1 microM 5-HT. The [Ca2+]i response decreased upon repeated challenges with 1 microM 5-HT, probably as a result of receptor desensitisation. Taken together, the data suggest that 5-HT acts at 5-HT2C receptors to increase [Ca2+]i in choroid plexus epithelial cells, both by liberating Ca2+ from intracellular stores and by activating a Ca2+ influx pathway.
Watson
J A
JA
School of Biological Sciences, University of Manchester, UK.
Elliott
A C
AC
Brown
P D
PD
D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002831:Choroid Plexus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000145:classification / Q000187:drug effects / Q000378:metabolism*; D015290:Second Messenger Systems; D012701:Serotonin / Q000378:metabolism* / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000494:pharmacology
D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin; D002118:Calcium