TY - JOUR
T1 - Differential coupling of D1 and D5 dopamine receptors to guanine nucleotide binding proteins in transfected GH4C1 rat somatomammotrophic cells
AU - Kimura, Kazuhiro
AU - Sela, Shifra
AU - Bouvier, Claudia
AU - Grandy, David K.
AU - Sidhu, Anita
PY - 1995/5
Y1 - 1995/5
N2 - D1 and D5 dopamine receptor genes, stably expressed in GH4C1 rat somatomammotrophic cells, display identical binding values and stimulate adenylate cyclase. Approximately 60% of D1 receptors were in the agonist high-affinity state and were converted to the low-affinity state by 100 μM guanyl-5'-ylimidodiphosphate [Gpp(NH)p]. Of the 48% of D5 receptors in the high-affinity state, only half were modulated by 100 μM Gpp(NH)p; in the presence of the G protein activator, AIF4 , the high-affinity sites of D5 receptors were abolished by Gpp(NH)p, suggesting tight coupling between D5 receptors and G proteins. The high-affinity sites of D1, but not D5, receptors were reduced after pertussis toxin treatment of cells. Thus, whereas D1 receptors in GH4C1 cells couple to both G(s) the G stimulatory protein, and a pertussis toxin-sensitive G protein, D5 receptors couple to G5 and a pertussis toxin-insensitive G protein. Neither D1 nor D5 receptors were able to stimulate phosphoinositide metabolism in these cells. The ability of D5, but not D1, receptors to couple to novel G proteins may be significant in assigning a functional role for these receptors.
AB - D1 and D5 dopamine receptor genes, stably expressed in GH4C1 rat somatomammotrophic cells, display identical binding values and stimulate adenylate cyclase. Approximately 60% of D1 receptors were in the agonist high-affinity state and were converted to the low-affinity state by 100 μM guanyl-5'-ylimidodiphosphate [Gpp(NH)p]. Of the 48% of D5 receptors in the high-affinity state, only half were modulated by 100 μM Gpp(NH)p; in the presence of the G protein activator, AIF4 , the high-affinity sites of D5 receptors were abolished by Gpp(NH)p, suggesting tight coupling between D5 receptors and G proteins. The high-affinity sites of D1, but not D5, receptors were reduced after pertussis toxin treatment of cells. Thus, whereas D1 receptors in GH4C1 cells couple to both G(s) the G stimulatory protein, and a pertussis toxin-sensitive G protein, D5 receptors couple to G5 and a pertussis toxin-insensitive G protein. Neither D1 nor D5 receptors were able to stimulate phosphoinositide metabolism in these cells. The ability of D5, but not D1, receptors to couple to novel G proteins may be significant in assigning a functional role for these receptors.
KW - Cell transfection
KW - Dopamine receptor
KW - G protein
KW - High-affinity binding sites
KW - Pertussis toxin
UR - http://www.scopus.com/inward/record.url?scp=0028922873&partnerID=8YFLogxK
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C2 - 7722495
AN - SCOPUS:0028922873
SN - 0022-3042
VL - 64
SP - 2118
EP - 2124
JO - Journal of Neurochemistry
JF - Journal of Neurochemistry
IS - 5
ER -