Advantages of heterologous expression of human D2long dopamine receptors in human neuroblastoma SH‐SY5Y over human embryonic kidney 293 cells

• Published in: British journal of pharmacology 2000-10, Vol.131 (3), p.514-520
• Main Authors: Alberts, Glen L, Pregenzer, Jeffrey F, Im, Wha Bin
• Format: Article
• Language: English
• Subjects: agonist‐induced GTPγ35S binding; Biological and medical sciences; Calcium Channels - metabolism; Catecholaminergic system; Cell receptors; Cell structures and functions; Cells, Cultured; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; Cloning, Molecular - methods; Dopamine Antagonists - pharmacology; Dopamine D2 Receptor Antagonists; Fundamental and applied biological sciences. Psychology; G protein‐couplings; Heterotrimeric GTP-Binding Proteins - metabolism; Human D2long dopamine receptor; human embryonic kidney 293 cells; Humans; immobilization of GTPγ35S‐bound Gα subunits; intrinsic efficacy; Kidney - cytology; Kidney - metabolism; Medical sciences; Molecular and cellular biology; Monoamines receptors (catecholamine, serotonine, histamine, acetylcholine); Neuroblastoma; Neurons - metabolism; Neuropharmacology; Neurotransmitters. Neurotransmission. Receptors; Pharmacology. Drug treatments; Raclopride - pharmacology; Receptors, Dopamine D2 - biosynthesis; Recombinant Proteins - metabolism; SH‐SY5Y cells; Spiperone - pharmacology; Tumor Cells, Cultured; Vertebrates: nervous system and sense organs
• ISSN: 0007-1188; 1476-5381
• DOI: 10.1038/sj.bjp.0703580

The human D2long dopamine receptor when expressed heterologously in a human neuronal cell line, SH‐SY5Y, produced more robust functional signals than when expressed in a human embryonic kidney cell line, HEK293. Quinpirole (agonist)‐induced GTPγ35S binding and high affinity sites were 3–4 fold greater in SH‐SY5Y than in HEK293 cells. N‐type Ca2+ channel currents present in SH‐SY5Y cells, but not HEK293 cells, were inhibited potently by quinpirole with a half‐maximal inhibitory concentration of 0.15±0.03 nM. Inhibition of adenylyl cyclases by agonists, on the other hand, was of similar potency and efficacy in the two cell lines. GTPγ35S‐Bound Gα subunits from quinpirole‐activated and solubilized membranes were monitored upon immobilization with various Gα‐specific antibodies. Gαi and Gαo subunits were highly labelled with GTPγ35S in SH‐SY5Y cells, but only Gαi subunits were labelled in HEK293 cells. The additional Go coupling in SH‐SY5Y cells could arise, at least in part, from the presence of Go coupled‐effectors, such as the N‐type Ca2+ channel, and may contribute to robust agonist‐induced GTPγ35S binding, which is a reliable means for measuring ligand intrinsic efficacy. It appears that expression of neuronal G protein‐coupled receptors in neuronal environments could reveal additional functional characteristics that are absent in non‐neuronal cell lines. This appears to be due to, at least in part, to the presence of neuron‐specific effectors. These findings underscore the importance of the cellular environment in which drug actions are examined, particularly in the face of intensive efforts to develop drugs for G protein‐coupled receptors of various origins. British Journal of Pharmacology (2000) 131, 514–520; doi:10.1038/sj.bjp.0703580