Evidence for opposing influences of cyclic GMP and cyclic AMP on force of contraction in mammalian myocardium. 1976

H Nawrath

The inotropic effects of the 8-Br-derivatives of cyclic GMP and cyclic AMP were investigated in guinea pig or rat auricles and papillary muscles from cats. In guinea pig auricles, 8-Br-cyclic GMP had a concentration-dependent negative inotropic effect, whereas 8-Br-cyclic AMP had a concentration-dependent positive inotropic effect. A negative inotropic effect of 8-Br-cyclic GMP in rat auricles was obtained with 30 times lower doses than in guinea pig auricles; the pacemaker activity of spontaneously beating rat right auricles did not change in response to 8-Br-cyclic GMP. In cat papillary muscles, 8-Br-cyclic GMP (3 X 10(-4) M) also produced a negative inotropic effect. In contrast, 8-Br-cyclic AMP (3 X 10(-4) M) did not affect force of contraction; however, after pretreatment with the strong phosphodiesterase inhibitor papaverine (2 X 10(-5) M) 8-Br-cyclic AMP (3 X 10(-4) M) had a strong positive inotropic effect also in cat papillary muscles. The results suggest opposite influences of cyclic GMP and cyclic AMP on force of contraction in mammalian myocardium.

UI MeSH Term Description Entries
D008297 Male Males
D009200 Myocardial Contraction Contractile activity of the MYOCARDIUM. Heart Contractility,Inotropism, Cardiac,Cardiac Inotropism,Cardiac Inotropisms,Contractilities, Heart,Contractility, Heart,Contraction, Myocardial,Contractions, Myocardial,Heart Contractilities,Inotropisms, Cardiac,Myocardial Contractions
D002415 Cats The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801) Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D004305 Dose-Response Relationship, Drug The relationship between the dose of an administered drug and the response of the organism to the drug. Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D005260 Female Females
D006152 Cyclic GMP Guanosine cyclic 3',5'-(hydrogen phosphate). A guanine nucleotide containing one phosphate group which is esterified to the sugar moiety in both the 3'- and 5'-positions. It is a cellular regulatory agent and has been described as a second messenger. Its levels increase in response to a variety of hormones, including acetylcholine, insulin, and oxytocin and it has been found to activate specific protein kinases. (From Merck Index, 11th ed) Guanosine Cyclic 3',5'-Monophosphate,Guanosine Cyclic 3,5 Monophosphate,Guanosine Cyclic Monophosphate,Guanosine Cyclic-3',5'-Monophosphate,3',5'-Monophosphate, Guanosine Cyclic,Cyclic 3',5'-Monophosphate, Guanosine,Cyclic Monophosphate, Guanosine,Cyclic-3',5'-Monophosphate, Guanosine,GMP, Cyclic,Guanosine Cyclic 3',5' Monophosphate,Monophosphate, Guanosine Cyclic
D006168 Guinea Pigs A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research. Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D000242 Cyclic AMP An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH. Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D051381 Rats The common name for the genus Rattus. Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus

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H Nawrath
November 1973, Biochemical and biophysical research communications,
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