Effects of adenine nucleosides and nucleotides on the isolated heart of the snail Helix aspersa and the slug Arion ater.
1. Adenine nucleosides and nucleotides were examined for pharmacological activity in hearts isolated from the snail Helix aspersa and the slug Arion ater. 2. Adenosine, AMP, ADP and ATP (above 100 microM) produced either an excitation or an inhibition in the isolated hearts of the snail and slug. 3. 2-Chloroadenosine, alpha, beta-methylene ATP and 2-methylthio ATP were inactive at concentrations up to 1 mM. 4. Responses were not blocked by any commonly accepted vertebrate purinoceptor antagonists, indicating that these purinoceptors are dissimilar to vertebrate purinoceptors and cannot be classified according to accepted purinoceptor classifications. 5. Electrical field stimulation of the snail heart produced frequency-dependent responses: 1-4 Hz produced predominantly excitation, 8-32 Hz predominantly inhibition. These responses were unaffected by the purines up 3 mM.
Department of Anatomy and Developmental Biology, University College London, U.K.
G E
GE
Knight
C H
CH
Hoyle
G
G
Burnstock
D000227:Adenine Nucleotides / Q000494:pharmacology*; D000241:Adenosine / Q000494:pharmacology*; D000818:Animals; D004210:Dissection; D004558:Electric Stimulation; D006321:Heart / Q000187:drug effects; D006372:Helix, Snails / Q000187:drug effects*; D066298:In Vitro Techniques; D008974:Mollusca / Q000187:drug effects*; D011684:Purine Nucleosides / Q000494:pharmacology*
D000227:Adenine Nucleotides; D011684:Purine Nucleosides; D000241:Adenosine