Inhibition of adenylyl cyclase activity by a homogeneous population of dopamine receptors: Selective blockade by antisera directed against Gi1 and/or Gi2

Sari E Izenwasser, Thomas E. Côté

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The 7315c pituitary tumor cell expresses a homogeneous population of dopamine receptors that are functionally similar to brain dopamine D2 receptors. [3H]-Sulpiride binding to 7315c cell homogenates was specific and saturable, and Ki values for compounds to compete for these sites were highly correlated with values for the same compounds at D2 receptors in brain. Dopamine maximally inhibited ∼65% of forskolin-stimulated cyclase activity in cell membranes. Some D2 agonists had lower efficacies, suggesting that some compounds are partial agonists at this receptor. Removal of GTP from the assay buffer or pretreatment of the tissue with pertussis toxin abolished the inhibition of adenylyl cyclase by dopamine. Immunodetection of most of the known Ga subunits revealed that Gi1, Gi2, Gi3, Go, Gq, and Gs are present in the 7315c membrane. Pretreatment with the AS antibody (which recognizes the C-terminal regions of Gαi1 and Gαi2) significantly attenuated the inhibition of adenylyl cyclase activity by dopamine, whereas antibodies to C-terminal regions of the other Ga subunits had no effect. These findings suggest that the dopamine D2 receptor regulates cyclase inhibition predominantly via Gi1 and/or Gi2 and that the 7315c tumor cells provide a useful model for studying naturally expressed dopamine D2 receptors in the absence of other dopamine receptor subtypes.

Original languageEnglish
Pages (from-to)1614-1621
Number of pages8
JournalJournal of Neurochemistry
Volume64
Issue number4
StatePublished - Apr 1 1995
Externally publishedYes

Fingerprint

Dopamine D2 Receptors
Dopamine Receptors
Adenylyl Cyclases
Immune Sera
Dopamine
Tumors
Brain
Cells
Population
Sulpiride
Antibodies
Pertussis Toxin
Pituitary Neoplasms
Colforsin
Cell membranes
Guanosine Triphosphate
Assays
Buffers
Cell Membrane
Tissue

Keywords

  • Cocaine
  • D dopamine receptor
  • Dopamine

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

Cite this

@article{db5222d8cc1e46f5ab317b9b7733fae5,
title = "Inhibition of adenylyl cyclase activity by a homogeneous population of dopamine receptors: Selective blockade by antisera directed against Gi1 and/or Gi2",
abstract = "The 7315c pituitary tumor cell expresses a homogeneous population of dopamine receptors that are functionally similar to brain dopamine D2 receptors. [3H]-Sulpiride binding to 7315c cell homogenates was specific and saturable, and Ki values for compounds to compete for these sites were highly correlated with values for the same compounds at D2 receptors in brain. Dopamine maximally inhibited ∼65{\%} of forskolin-stimulated cyclase activity in cell membranes. Some D2 agonists had lower efficacies, suggesting that some compounds are partial agonists at this receptor. Removal of GTP from the assay buffer or pretreatment of the tissue with pertussis toxin abolished the inhibition of adenylyl cyclase by dopamine. Immunodetection of most of the known Ga subunits revealed that Gi1, Gi2, Gi3, Go, Gq, and Gs are present in the 7315c membrane. Pretreatment with the AS antibody (which recognizes the C-terminal regions of Gαi1 and Gαi2) significantly attenuated the inhibition of adenylyl cyclase activity by dopamine, whereas antibodies to C-terminal regions of the other Ga subunits had no effect. These findings suggest that the dopamine D2 receptor regulates cyclase inhibition predominantly via Gi1 and/or Gi2 and that the 7315c tumor cells provide a useful model for studying naturally expressed dopamine D2 receptors in the absence of other dopamine receptor subtypes.",
keywords = "Cocaine, D dopamine receptor, Dopamine",
author = "Izenwasser, {Sari E} and C{\^o}t{\'e}, {Thomas E.}",
year = "1995",
month = "4",
day = "1",
language = "English",
volume = "64",
pages = "1614--1621",
journal = "Journal of Neurochemistry",
issn = "0022-3042",
publisher = "Wiley-Blackwell",
number = "4",

}

TY - JOUR

T1 - Inhibition of adenylyl cyclase activity by a homogeneous population of dopamine receptors

T2 - Selective blockade by antisera directed against Gi1 and/or Gi2

AU - Izenwasser, Sari E

AU - Côté, Thomas E.

PY - 1995/4/1

Y1 - 1995/4/1

N2 - The 7315c pituitary tumor cell expresses a homogeneous population of dopamine receptors that are functionally similar to brain dopamine D2 receptors. [3H]-Sulpiride binding to 7315c cell homogenates was specific and saturable, and Ki values for compounds to compete for these sites were highly correlated with values for the same compounds at D2 receptors in brain. Dopamine maximally inhibited ∼65% of forskolin-stimulated cyclase activity in cell membranes. Some D2 agonists had lower efficacies, suggesting that some compounds are partial agonists at this receptor. Removal of GTP from the assay buffer or pretreatment of the tissue with pertussis toxin abolished the inhibition of adenylyl cyclase by dopamine. Immunodetection of most of the known Ga subunits revealed that Gi1, Gi2, Gi3, Go, Gq, and Gs are present in the 7315c membrane. Pretreatment with the AS antibody (which recognizes the C-terminal regions of Gαi1 and Gαi2) significantly attenuated the inhibition of adenylyl cyclase activity by dopamine, whereas antibodies to C-terminal regions of the other Ga subunits had no effect. These findings suggest that the dopamine D2 receptor regulates cyclase inhibition predominantly via Gi1 and/or Gi2 and that the 7315c tumor cells provide a useful model for studying naturally expressed dopamine D2 receptors in the absence of other dopamine receptor subtypes.

AB - The 7315c pituitary tumor cell expresses a homogeneous population of dopamine receptors that are functionally similar to brain dopamine D2 receptors. [3H]-Sulpiride binding to 7315c cell homogenates was specific and saturable, and Ki values for compounds to compete for these sites were highly correlated with values for the same compounds at D2 receptors in brain. Dopamine maximally inhibited ∼65% of forskolin-stimulated cyclase activity in cell membranes. Some D2 agonists had lower efficacies, suggesting that some compounds are partial agonists at this receptor. Removal of GTP from the assay buffer or pretreatment of the tissue with pertussis toxin abolished the inhibition of adenylyl cyclase by dopamine. Immunodetection of most of the known Ga subunits revealed that Gi1, Gi2, Gi3, Go, Gq, and Gs are present in the 7315c membrane. Pretreatment with the AS antibody (which recognizes the C-terminal regions of Gαi1 and Gαi2) significantly attenuated the inhibition of adenylyl cyclase activity by dopamine, whereas antibodies to C-terminal regions of the other Ga subunits had no effect. These findings suggest that the dopamine D2 receptor regulates cyclase inhibition predominantly via Gi1 and/or Gi2 and that the 7315c tumor cells provide a useful model for studying naturally expressed dopamine D2 receptors in the absence of other dopamine receptor subtypes.

KW - Cocaine

KW - D dopamine receptor

KW - Dopamine

UR - http://www.scopus.com/inward/record.url?scp=0028908653&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0028908653&partnerID=8YFLogxK

M3 - Article

C2 - 7891089

AN - SCOPUS:0028908653

VL - 64

SP - 1614

EP - 1621

JO - Journal of Neurochemistry

JF - Journal of Neurochemistry

SN - 0022-3042

IS - 4

ER -