Effects of neuropeptide FF on intracellular Ca2+ in mouse spinal ganglion neurons.
Intracellular Ca2+ was measured in freshly dissociated mouse dorsal root ganglion neurons by using Fluo3 as fluorescent Ca2+ probe. Short perifusions (5-10 s) with 30 mM K+ induced a sharp rise in fluorescence due to the entry of Ca2+ ions, in particular through L and N voltage sensitive Ca2+ channels opened by the action potentials that were triggered by depolarization. Perifusions with 1 or 10 nM (1DMe)Y8Fa (DYL(NMe)FQPQRFamide), a neuropeptide FF analog, suppressed the rise in fluorescence induced by short (5-10 s) K+ perifusions within 30 min. However, when K+ perifusions of longer duration were applied, Fluo3 fluorescence rose after an increased latency. Two other analogs, (2DMe)Y8Fa (DYDL(NMe)FQPQRFamide) and (3D)Y8Fa (DYDLDFQPQRFamide), had the same effect; similarly neuropeptide FF (FLFQPQRFamide, 1 nM, 30 min) reduced intracellular Ca2+ rise during depolarization. These features indicate that neuropeptide FF and its analogs exert their pharmacological effects by reducing the [Ca2+]i transient induced by short depolarizations.
Roumy
M
M
Laboratoire de Pharmacologie et Toxicologie Fondamentales, CNRS, Toulouse, France.
Zajac
J M
JM
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects* / Q000502:physiology; D005727:Ganglia, Spinal / Q000378:metabolism*; D008297:Male; D051379:Mice; D009474:Neurons / Q000378:metabolism*; D009479:Neuropeptides / Q000494:pharmacology*; D009842:Oligopeptides / Q000494:pharmacology*
D015220:Calcium Channels; D009479:Neuropeptides; D009842:Oligopeptides; C053651:phenylalanyl-leucyl-phenylalanyl-glutaminyl-prolyl-glutaminyl-arginyl-phenylalaninamide; D002118:Calcium