Neuropeptide Y increases intracellular calcium in rat pinealocytes.
The pineal gland is mainly innervated by sympathetic fibres containing noradrenaline (NA) and neuropeptide Y (NPY). NA released at night stimulates melatonin synthesis via a beta1-adrenergic-induced increase in cyclic adenosine monophosphate (cAMP) concentration potentiated by an alpha1-adrenergic-induced increase in Ca2+ concentration. We previously showed that NPY acted on presynaptic Y2 receptors inhibiting NA release and on postsynaptic Y1 receptors stimulating melatonin synthesis. Here we used Fura-2 imaging to assess the effect of NPY on the intracellular Ca2+ concentration, [Ca2+]i, in cultured rat pineal cells. In 84% of cells, on average, 10 nM NPY induced a progressive rise of [Ca2+]i from its basal value of 102+/-3 nM to a plateau of 180+/-6 nM (n = 467 cells), which lasted the time of NPY application. This effect of NPY appeared dependent on extracellular Ca2+.
Simonneaux
V
V
Neurobiologie des Fonctions Rythmiques et Saisonnières, UMR-CNRS 7518, Université Louis Pasteur, Strasbourg, France. simonneaux@neurochem.u-strasbg.fr
Rodeau
J L
JL
Calgari
C
C
Pévet
P
P
D000320:Adrenergic Fibers / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000493:pharmacokinetics; D002478:Cells, Cultured; D005456:Fluorescent Dyes; D016257:Fura-2; D009478:Neuropeptide Y / Q000494:pharmacology*; D010870:Pineal Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D005456:Fluorescent Dyes; D009478:Neuropeptide Y; D002118:Calcium; D016257:Fura-2