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A heptadecapeptide was identified and purified from porcine brain tissue as a ligand for an orphan heterotrimeric GTP-binding protein (G protein)-coupled receptor (LC132) that is similar in sequence to opioid receptors. This peptide, orphanin FQ, has a primary structure reminiscent of that of opioid peptides. Nanomolar concentrations of orphanin FQ(More)
An aspartate residue corresponding to aspartate-80 of dopamine D2 receptors is strictly conserved among receptors that couple to guanine nucleotide-binding proteins. Mutation of this residue alters the function of several classes of neurotransmitter receptors. Dopamine D2 receptors couple to the guanine nucleotide-binding protein Gi to inhibit adenylyl(More)
BACKGROUND AND PURPOSE Purinoceptors containing the P2X3 subunit (P2X3 homotrimeric and P2X2/3 heterotrimeric) are members of the P2X family of ion channels gated by ATP and may participate in primary afferent sensitization in a variety of pain-related diseases. The current work describes the in vitro pharmacological characteristics of AF-353, a novel,(More)
Strict pharmacological selectivity in families of structurally related ligands and receptors may result from a key process in evolution aiming at increasing diversity in neurotransmission. An intriguing example of such exclusive specificity can be found in the newly discovered orphanin FQ (OFQ) system when it is compared with the opioid system. Both OFQ and(More)
A human dopamine transporter cDNA was cloned and transfected into COS-7 cells, a cell line that lacks vesicular storage and release mechanisms. Cells expressing the dopamine transporter acquired the capacity to take up and release dopamine via the transporter. Ionic conditions that stimulate inside-out transport in vivo, such as depolarizing concentrations(More)
Multiple genetic polymorphisms of the human dopamine D4 receptor (hD4R) have been identified including a 12 bp repeat in exon 1 associated with a psychotic condition called delusional disorder. Competition binding assays revealed minor pharmacological differences between the recombinant A1 (normal) and A2 (delusional) proteins with respect to quinpirole and(More)
We have characterized the in vitro binding of a new ligand, [125I]epidepride, and used this substituted benzamide to assess the sensitivity of dopamine D-2 receptors to sodium. Both direct and indirect binding studies with [125I]epidepride and unlabeled epidepride, respectively, demonstrated that the affinity of D-2 receptors for the ligand was decreased(More)
The heptadecapeptide orphanin FQ (OFQ) has been identified as the endogenous ligand for a G protein-coupled receptor (OFQ-R), which, despite its high degree of sequence similarity to opioid receptors, fails to bind opioid ligands. We developed two radioligands for the OFQ-R: a tritiated native OFQ peptide ([3H]OFQ) and a radioiodinated form in which Leu14(More)
The heptadecapeptide orphanin FQ (OFQ) is a recently discovered neuropeptide that exhibits structural features reminiscent of the opioid peptides and that is an endogenous ligand to a G protein-coupled receptor sequentially related to the opioid receptors. We have cloned both the human and rat cDNAs encoding the OFQ precursor proteins, to investigate(More)
We recently cloned a complementary DNA for the rat dopamine D-2 receptor, making it possible to create cell lines expressing this receptor. A cell line (LZR1) was created by transfecting the D-2 cDNA (RGB-2) into mouse fibroblast Ltk- cells. LZR1 cells, previously described as L-RGB2Zem-1 cells, express a high density of D-2 receptors, whereas the wild-type(More)