Neuropeptide Y inhibits Ca2+ influx into cultured dorsal root ganglion neurones of the rat via a Y2 receptor.
1. The identity of the neuropeptide Y (NPY) receptor associated with the observed inhibition of neuronal Ca2+ currents (ICa) in rat dorsal root ganglion (DRG) cells has been established on the basis of agonist responses to analogues and carboxy terminal (C-terminal) fragments of the NPY molecule. 2. Whole cell barium currents (IBa) in DRG cells were reversibly inhibited by 100 nM NPY, 100 nM PYY and C-terminal fragments of NPY in a manner that correlated with the length of the NPY fragments (for inhibition of the IBa NPY = PYY greater than NPY2-36 greater than NPY13-36 greater than NPY16-36 greater than NPY18-36 much greater than NPY25-36). 3. C-terminal fragments of NPY were also effective in reversibly reducing the ICa, the associated increase in the intracellular Ca2+ concentration [( Ca2+]i) and the increased [Ca2+]i produced by evoked action potentials in the DRG cells. In addition, a Ca(2+)-activated Cl- conductance was also reversibly reduced by NPY fragments only when accompanied by a reduction in Ca2+ entry. 4. We conclude that the Y2 receptor for neuropeptide Y is coupled to inhibition of Ca2+ influx via voltage-sensitive calcium channels in DRG cells.
Bleakman
D
D
Department of Pharmacological and Physiological Sciences, University of Chicago, Illinois.
Colmers
W F
WF
Fournier
A
A
Miller
R J
RJ
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D001464:Barium / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004594:Electrophysiology; D016257:Fura-2; D005727:Ganglia, Spinal / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism; D009451:Neuroeffector Junction / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D009478:Neuropeptide Y / Q000494:pharmacology*; D018377:Neurotransmitter Agents / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D017476:Receptors, Neuropeptide Y; D017981:Receptors, Neurotransmitter / Q000378:metabolism*
D007473:Ion Channels; D009478:Neuropeptide Y; D018377:Neurotransmitter Agents; D010455:Peptides; D017476:Receptors, Neuropeptide Y; D017981:Receptors, Neurotransmitter; D001464:Barium; D002118:Calcium; D016257:Fura-2