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Responses of the rectum and oesophagus of the snail Helix aspersa to purine nucleotides and nucleosides.

Knight, GE; Hoyle, CH; Burnstock, G; (1992) Responses of the rectum and oesophagus of the snail Helix aspersa to purine nucleotides and nucleosides. Comp Biochem Physiol C , 103 (3) pp. 535-540.

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Abstract

1. Purine compounds were examined for pharmacological activity in the rectum and oesophagus of the garden snail Helix aspersa. 2. In the rectum, adenosine, AMP, ADP and ATP (above 10 microM) and acetylcholine (above 1 nM) consistently caused concentration-dependent contractions. The slope of the dose-response curve for ADP in the rectum was significantly steeper than for the other purine compounds. The contractile responses to the nucleotides and acetylcholine, but not adenosine, were selectively potentiated by physostigmine (1 microM). Atropine (1 microM) and tubocurarine (30 microM) failed to block the responses to the purines or acetylcholine. 3. In the oesophagus, adenosine, AMP, ADP and ATP (above 10 microM) and acetylcholine (above 1 nM) caused concentration-dependent contractions that were antagonised by atropine (1 microM). Tubocurarine (30 microM) failed to block the responses to the purine compounds or acetylcholine. Physostigmine (1 microM) potentiated the responses to ADP and acetylcholine but not ATP, AMP or adenosine. 4. In both the rectum and the oesophagus, the synthetic analogues of purine compounds including 2-chloroadenosine, alpha,beta-methylene ATP and 2-methylthio ATP were inactive up to a concentration of 100 microM. 5. Electrical field stimulation of the rectum and oesophagus produced consistent contractions which were unaffected by atropine (1 microM), tubocurarine (30 microM) or physostigmine (1 microM). These responses were not modulated by any of the purine compounds or their stable analogues. 6. The responses obtained appear novel even within known invertebrate purinergic systems, suggesting a differentiation of purinoceptor subtypes in this species.(ABSTRACT TRUNCATED AT 250 WORDS)

Type: Article
Title: Responses of the rectum and oesophagus of the snail Helix aspersa to purine nucleotides and nucleosides.
Location: England
Keywords: Acetylcholine, Animals, Electric Stimulation, Esophagus, Helix (Snails), Purine Nucleosides, Purine Nucleotides, Purinergic Antagonists, Rectum
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences > Neuro, Physiology and Pharmacology
URI: http://discovery.ucl.ac.uk/id/eprint/10027327
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