scholarly journals Involvement of the inhibitory GTP-binding regulatory protein and a low-affinity benzodiazepine receptor in the inhibitory effect of diazepam on rat brain adenylate cyclase system.

1988 ◽  
Vol 47 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Tomonori KUROKAWA ◽  
Toshio DAN'URA ◽  
Atsushi YAMASHITA ◽  
Yasutomo UNE ◽  
Sadahiko ISHIBASHI
Keyword(s):  
Adenylate Cyclase ◽  
Rat Brain ◽  
Regulatory Protein ◽  
Benzodiazepine Receptor ◽  
Inhibitory Effect ◽  
Adenylate Cyclase System ◽  
Gtp Binding

scholarly journals Evidence for the existence of an Ns-type regulatory protein in Trypanosoma cruzi membranes

1986 ◽  
Vol 237 (3) ◽  
pp. 913-917 ◽  
Author(s):  
C D Eisenschlos ◽  
A A Paladini ◽  
L Molina y Vedia ◽  
H N Torres ◽  
M M Flawiá
Keyword(s):  
Membrane Proteins ◽  
Trypanosoma Cruzi ◽  
Adenylate Cyclase ◽  
Cholera Toxin ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Regulatory Protein ◽  
Adenylate Cyclase System ◽  
Gtp Binding ◽  
Polypeptide Band

The existence of a GTP-binding protein of the Ns type in Trypanosoma cruzi was explored. Epimastigote membranes were labelled by cholera toxin in the presence of [adenine-14C]NAD+. After SDS/polyacrylamide-gel electrophoresis of extracted membrane proteins, a single labelled polypeptide band of apparent Mr approx. 45,000 was detected. Epimastigote cells were treated with N-ethylmaleimide and electrofused to lymphoma S49 cells lacking the Ns protein. Evidence indicates that in such electrofusion-generated cell hybrids a heterologous adenylate cyclase system was reconstituted with the Ns protein provided by T. cruzi epimastigotes.

scholarly journals Mechanism of acetylcholine-induced inhibition of Ca current in bullfrog atrial myocytes.

1990 ◽  
Vol 96 (4) ◽  
pp. 865-885 ◽  
Author(s):  
T Nakajima ◽  
S Wu ◽  
H Irisawa ◽  
W Giles
Keyword(s):  
Adenylate Cyclase ◽  
Binding Protein ◽  
Cell Voltage ◽  
Inhibitory Effect ◽  
Atrial Myocytes ◽  
Ca Current ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Subsequent Application ◽  
Gamma S

The mechanism of the anti-beta-adrenergic action of acetylcholine (ACh) on Ca current, ICa, was examined using the tight-seal, whole-cell voltage clamp technique in single atrial myocytes from the bullfrog. Both isoproterenol (ISO) and forskolin increased ICa dose dependently. After ICa had been enhanced maximally by ISO (10(-6) M), subsequent application of forskolin (50 microM) did not further increase ICa, suggesting that ISO and forskolin increase ICa via a common biochemical pathway, possibly by stimulation of adenylate cyclase. ACh (10(-5) M) completely inhibited the effect of low doses of forskolin (2 x 10(-6) M), as well as ISO, but it failed to block the effects of high doses of forskolin (greater than 5 x 10(-5) M). Intracellular application of cyclic AMP (cAMP) also increased ICa. ACh (10(-5) M) failed to inhibit this cAMP effect, indicating that the inhibitory action of ACh occurs at a site proximal to the production of cAMP. ACh (10(-5) M) also activated an inwardly rectifying K+ current IK(ACh). Intracellular application of a nonhydrolyzable GTP analogue, GTP gamma S (5 X 10(-4) M), activated IK(ACh) within several minutes; subsequent application of ACh (10(-5) M) did not increase IK(ACh) further. These results demonstrate that a GTP-binding protein coupled to these K+ channels can be activated maximally by GTP gamma S even in the absence of ACh. Intracellular application of GTP gamma S also strongly inhibited the effect of ISO on ICa in the absence of ACh. Pertussis toxin (IAP) completely prevented both the inhibitory effect of ACh on ICa and the ACh-induced activation of IK(ACh). GTP gamma S (50 microM-1 mM) alone did not increase ICa significantly; however, when ISO was applied first, GTP gamma S (5 x 10(-4) M) gradually inhibited the ISO effect on ICa. These results indicate that ACh antagonizes the effect of ISO on ICa via a GTP-binding protein (Gi and/or Go). This effect may be mediated through a direct inhibition by the alpha-subunit of Gi which is coupled to the adenylate cyclase.

scholarly journals “Leaky” Epidermal Cells Contain a Complete Receptor-Mediated Adenylate Cyclase System with an Accessible GTP Regulatory Protein

1983 ◽  
Vol 81 (3) ◽  
pp. 241-245 ◽  
Author(s):  
Junji Takeda ◽  
Kenji Adachi ◽  
Kenneth M. Halprin ◽  
Osamu Nemoto ◽  
Victor Levine ◽  
...  
Keyword(s):  
Adenylate Cyclase ◽  
Regulatory Protein ◽  
Epidermal Cells ◽  
Adenylate Cyclase System
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