Role of cyclic nucleotides in the effect of transmitters on the heart of Helix pomatia L.

Katalin S.-Rózsa, T. Kiss

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Studying the membrane effect of the substances relating to the second messenger system on the Helix heart it was found: 1. 1. At the beginning of their application cAMP, DBcAMP, theophylline and imidazole increase diastolic depolarization, the duration of the plateau phase and the frequency of the spontaneous action potentials. At the second period of their action, the amplitude of the action potentials decreased then the generator potential ceased. 2. 2. The above substances depolarize or hyperpolarize the membrane only slightly, synchronously lowering membrane resistance. 3. 3. The changes in the different phases of the action potentials are attributed to the decrease in K-permeability and increase in Ca-permeability. During the application of cyclic nucleotides the alterations in permeability were only secondary appearing as a consequence of phosphorylation of the membrane components. 4. 4. After pretreatment with cyclic nucleotides or theophylline the 5HT and ACh failed to affect the membrane of Helix heart. The simultaneous application of 5HT with cyclic nucleotides decreased, while with theophylline increased the resistance of the surface membrane, but in the presence of ACh both the cyclic nucleotides and theophylline caused a decrease in membrane resistance. 5. 5. The changes in membrane effects of the above transmitters can be explained by prolonged alteration of permeability caused by cyclic nucleotides. The effect of DA was not blocked after treatment of the heart with cyclic nucleotides or theophylline. On the contrary, the potentiation of DA effect and the decrease in membrane resistance was observed.

Original languageEnglish
Pages (from-to)13-16
Number of pages4
JournalComparative Biochemistry and Physiology. Part C, Comparative
Volume53
Issue number1
DOIs
Publication statusPublished - 1976

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Cyclic Nucleotides
Membranes
Theophylline
Permeability
Action Potentials
Bucladesine
Second Messenger Systems
Phosphorylation

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Role of cyclic nucleotides in the effect of transmitters on the heart of Helix pomatia L. / S.-Rózsa, Katalin; Kiss, T.

In: Comparative Biochemistry and Physiology. Part C, Comparative, Vol. 53, No. 1, 1976, p. 13-16.

Research output: Contribution to journalArticle

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