Aporphines. 36. Dopamine receptor interactions of trihydroxyaporphines. Synthesis, radioreceptor binding, and striatal adenylate cyclase stimulation of 2,10,11-trihydroxyaporphines in comparison with other hydroxylated aporphines

1981 ◽  
Vol 24 (12) ◽  
pp. 1440-1445 ◽  
Author(s):  
John L. Neumeyer ◽  
George W. Arana ◽  
Say Jong Law ◽  
Jeffrey S. Lamont ◽  
Nora S. Kula ◽  
...  
Keyword(s):  
Adenylate Cyclase ◽  
Dopamine Receptor ◽  
Receptor Interactions ◽  
Adenylate Cyclase Stimulation ◽  
Stimulation Of

scholarly journals Agonist regulation of adenylate cyclase activity in neuroblastoma × glioma hybrid NG108-15 cells transfected to co-express adenylate cyclase type II and the β2-adrenoceptor. Evidence that adenylate cyclase is the limiting component for receptor-mediated stimulation of adenylate cyclase activity

1996 ◽  
Vol 318 (3) ◽  
pp. 1033-1039 ◽  
Author(s):  
David J. MACEWAN ◽  
Gun-Do KIM ◽  
Graeme MILLIGAN
Keyword(s):  
Adenylate Cyclase ◽  
Partial Agonist ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Intrinsic Activity ◽  
Type Ii ◽  
Guanine Nucleotide ◽  
Maximal Output ◽  
Adenylate Cyclase Stimulation ◽  
Stimulation Of

Stable cell lines, derived from NG108-15 cells and transfected to express both the β2-adrenoceptor and adenylate cyclase type II, were produced and examined. The absence of adenylate cyclase type II in the parental cells and its presence in these clones was demonstrated by reverse transcriptase-PCR. Total cellular levels of adenylate cyclase were increased in a number of clones between 3- and 8-fold, as assessed by guanine nucleotide-stimulated specific high-affinity binding of [3H]forskolin to cellular membranes. Basal adenylate cyclase activity was markedly elevated compared with a clone expressing similar levels of the β2-adrenoceptor in the absence of adenylate cyclase type II. Each of NaF, forskolin and guanosine 5´-[β,γ-imido]triphosphate (a poorly hydrolysed analogue of GTP) produced substantially higher levels of adenylate cyclase activity in membranes of the clones positive for expression of adenylate cyclase type II than was achieved with the parental cells. Both isoprenaline, acting at the introduced β2-adrenoceptor, and iloprost, acting at the endogenously expressed IP prostanoid receptor, stimulated adenylate cyclase activity to much higher levels in the clones expressing adenylate cyclase type II compared with the clone lacking this adenylate cyclase; however, the concentration–effect curves for adenylate cyclase stimulation by these two agonists were not different between parental cells and clones overexpressing adenylate cyclase type II. A maximally effective concentration of the β-adrenoceptor partial agonist ephedrine displayed similar intrinsic activity and potency to stimulate adenylate cyclase in membranes of clones both with and without adenylate cyclase type II. Both secretin and 5´-N-ethylcarboxamidoadenosine (acting at an endogenous A2 adenosine receptor) were also able to produce substantially greater maximal activations of adenylate cyclase in the clones expressing excess adenylate cyclase type II, without alterations in agonist intrinsic activity or potency. These results demonstrate that the maximal output of the stimulatory arm of the adenylate cyclase cascade can be increased by increasing total levels of adenylate cyclase in the genetic background of NG108-15 cells.

Comparison of renal and osseous binding of parathyroid hormone and hormonal fragments

1985 ◽  
Vol 249 (5) ◽  
pp. E437-E446 ◽  
Author(s):  
M. Demay ◽  
J. Mitchell ◽  
D. Goltzman
Keyword(s):  
Parathyroid Hormone ◽  
Adenylate Cyclase ◽  
Osteosarcoma Cells ◽  
Binding Studies ◽  
Intact Pth ◽  
Amino Terminal ◽  
Adenylate Cyclase Activation ◽  
Adenylate Cyclase Stimulation ◽  
Bovine Parathyroid Hormone ◽  
Stimulation Of

We compared receptor binding and adenylate cyclase stimulation of intact bovine parathyroid hormone (bPTH)-(1-84) and the synthetic amino-terminal fragments, bPTH-(1-34) and rat PTH (rPTH)-(1-34). Radioligands for binding studies were prepared by the lactoperoxidase technique and purified by high-pressure liquid chromatography. In both canine renal membranes and cloned rat osteosarcoma cells the amino-terminal fragments bound to a single order of sites; the affinity of rPTH-(1-34) exceeded that of bPTH-(1-34), correlating with its higher potency in stimulating adenylate cyclase. In studies with oxidized bPTH-(1--84), the middle and carboxyl regions of intact PTH were found to bind to both tissues but with higher affinity to osteosarcoma cells than to renal membranes. Our results demonstrate that rPTH-(1--34) is the most favorable probe of amino-terminal PTH binding and the most potent of the PTH peptides in stimulating renal and osseous adenylate cyclase. The results also show that midregion and carboxyl determinants within intact PTH contribute to hormone binding, which does not correlate with adenylate cyclase activation and appears more significant for skeletal than for renal binding.

scholarly journals Pharmacological and Biochemical Evidence for the Existence of Two Categories of Dopamine Receptor

1984 ◽  
Vol 11 (S1) ◽  
pp. 114-117 ◽  
Author(s):  
J.W. Kebabian ◽  
M. Beaulieu ◽  
Y. Itoh
Keyword(s):  
Adenylate Cyclase ◽  
Dopamine Receptors ◽  
Dopamine Receptor ◽  
First Generation ◽  
Binding Assays ◽  
Biochemical Evidence ◽  
D 2 Receptors ◽  
Selective Agonists ◽  
Camp Formation ◽  
Stimulation Of

ABSTRACTEvidence supporting the validity of the ‘two dopamine receptor’ hypothesis is presented. The availability of the ‘first generation’ of selective agonists and antagonists of the D-1 and the D-2 dopamine receptors provides pharmacological support for the hypothesis. The demonstration that stimulation of the D-2 receptor either inhibits or has no effect upon adenylate cyclase activity while stimulation of the D-1 receptor enhances cAMP formation provides biochemical support for the hypothesis. Finally, binding assays demonstrating two affinity states for the D-1 and the D-2 receptors are briefly discussed.

scholarly journals Epidermal Adenylate Cyclase: Stimulation of The Histamine (H2) Receptor by Tolazoline

1977 ◽  
Vol 69 (5) ◽  
pp. 442-445 ◽  
Author(s):  
Hajime Iizuka ◽  
Kenji Adachi ◽  
Kenneth M Halprin ◽  
Victor. Levine
Keyword(s):  
Adenylate Cyclase ◽  
Histamine H2 Receptor ◽  
H2 Receptor ◽  
Adenylate Cyclase Stimulation ◽  
Stimulation Of

PGE2, forskolin, and cholera toxin interactions in modulating NaCl transport in mouse mTALH

1984 ◽  
Vol 247 (5) ◽  
pp. F784-F792 ◽  
Author(s):  
R. M. Culpepper ◽  
T. E. Andreoli
Keyword(s):  
Adenylate Cyclase ◽  
Cholera Toxin ◽  
Thick Ascending Limb ◽  
Nacl Transport ◽  
Medullary Thick Ascending Limb ◽  
Maximal Stimulation ◽  
Chloride Absorption ◽  
Receptor Interactions ◽  
Transepithelial Voltage ◽  
Stimulation Of

Prostaglandin E2 (PGE2) inhibits the ADH-stimulated components of the lumen-positive transepithelial voltage (Ve) and of net chloride absorption (JnetCl) in the isolated microperfused mouse medullary thick ascending limb of Henle (mTALH), presumably by interfering with the ADH-dependent intracellular accumulation of cAMP. These experiments examined the interactions of PGE2 with two nonhormonal stimulators of adenylate cyclase--cholera toxin and forskolin--in an attempt to evaluate the means by which PGE2 inhibits ADH-stimulated transport in these mTALH segments. Forskolin (FSK) stimulated Ve in the mTALH with half-maximal stimulation at 1.4 X 10(-7) M FSK. PGE2 had no effect on FSK stimulation of Ve; 10(-6) M FSK reversed completely the PGE2 inhibition of ADH-stimulated Ve. A low concentration of cholera toxin, 5 X 10(-13) M, stimulated Ve and JnetCl in the mTALH; 10(-6) M PGE2 inhibited the stimulation by cholera toxin; and 10(-6) M FSK reversed the PGE2 inhibition of both Ve and JnetCl in cholera toxin-stimulated mTALH. A higher concentration of cholera toxin, 10(-10) M, stimulated Ve and JnetCl to values identical to those seen with maximal concentrations of ADH, but PGE2 did not inhibit the increments in either Ve or JnetCl produced by 10(-10) M cholera toxin. PGE2 appears to inhibit ADH stimulation of NaCl transport in mTALH by an action distal to hormone-receptor interactions yet proximal to the catalytic subunit of adenylate cyclase.

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