Interaction between alpha 2-adrenergic and NPY receptor pathways in human erythroleukemia cells.
Neuropeptide Y (NPY) appears to be a transmitter of the sympathetic nervous system, and its actions are similar to those of alpha 2-adrenergic receptor stimulation. In human erythroleukemia (HEL) cells, both NPY and epinephrine (acting through alpha 2-adrenergic receptors) inhibit adenylate cyclase and mobilize intracellular Ca++. We investigated possible interactions between NPY and epinephrine. In radioligand binding assays NPY did not alter antagonist or agonist binding to alpha 2-adrenergic receptors. NPY and epinephrine did not act synergistically to elevate intracellular Ca++. Neither agent alone, nor both together, affected the intracellular pH of HEL cells. Preincubation with NPY (like epinephrine) redistributed the alpha 2-adrenergic receptors away from the cell surface and into a sequestered pool.
Motulsky
H J
HJ
Department of Pharmacology, University of California, San Diego, La Jolla 92093.
Michel
M C
MC
D002118:Calcium / Q000378:metabolism; D004357:Drug Synergism; D004837:Epinephrine / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism* / Q000473:pathology; D009478:Neuropeptide Y / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D017476:Receptors, Neuropeptide Y; D017981:Receptors, Neurotransmitter / Q000502:physiology*; D014407:Tumor Cells, Cultured
D009478:Neuropeptide Y; D011942:Receptors, Adrenergic, alpha; D017476:Receptors, Neuropeptide Y; D017981:Receptors, Neurotransmitter; D002118:Calcium; D004837:Epinephrine