The effect of ATP, GTP and cAMP on the cGMP-dependent conductance of the fragments from frog rod plasma membrane.
Using a 'patch-clamp' method in the 'inside-out' configuration, ATP, ADP, AMP-PCP and AMP-PNP have been shown to increase the cGMP-dependent component of the rod plasma membrane conductance 2-4-fold and GTP, GDP but not GMP or nonhydrolyzable GTP analogs GMP-PNP and GTP-gamma-S to abolish the ATP action. The ATP and GTP effects were observed at [EDTA] = 1 mM when magnesium and calcium ions were absent. In about half of the experiments the cGMP-dependent conductance was shown to be increased by cAMP in the micromolar concentration range by 10-50%, the cAMP action did not depend on the presence of nucleoside triphosphates. In vivo ATP, GTP and cAMP are assumed to modulate the sensitivity of the photoreceptor plasma membrane to cGMP.
Filatov
G N
GN
Institute of Biological Physics, USSR Academy of Sciences, Pushchino, Moscow Region.
Jainazarov
A B
AB
Kolesnikov
S S
SS
Lyubarsky
A L
AL
Fesenko
E E
EE
D000227:Adenine Nucleotides / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D000242:Cyclic AMP / Q000494:pharmacology*; D006152:Cyclic GMP / Q000494:pharmacology*; D004347:Drug Interactions; D004492:Edetic Acid / Q000494:pharmacology; D004553:Electric Conductivity; D006150:Guanine Nucleotides / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000494:pharmacology*; D010786:Photoreceptor Cells / Q000187:drug effects / Q000502:physiology*; D011896:Rana temporaria; D014982:Xenopus laevis
D000227:Adenine Nucleotides; D006150:Guanine Nucleotides; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D004492:Edetic Acid; D000242:Cyclic AMP; D006152:Cyclic GMP